diff --git a/.travis.yml b/.travis.yml
index 46bb847e6..19535d23b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -28,7 +28,7 @@ before_install:
   - conda config --set always_yes yes --set changeps1 no
   - conda update -q conda
   - conda info -a
-  - conda create -q -n test-environment python=$TRAVIS_PYTHON_VERSION numpy scipy h5py=2.5 pandas
+  - conda create -q -n test-environment python=$TRAVIS_PYTHON_VERSION six numpy scipy h5py=2.5 pandas
   - source activate test-environment
 
   # Install GCC, MPICH, HDF5, PHDF5
diff --git a/scripts/openmc-convert-mcnp70-data b/scripts/openmc-convert-mcnp70-data
index e68bd848e..a3081e3ee 100755
--- a/scripts/openmc-convert-mcnp70-data
+++ b/scripts/openmc-convert-mcnp70-data
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 from __future__ import print_function
-from argparse import ArgumentParser
+import argparse
 from collections import defaultdict
 import glob
 import os
@@ -9,8 +9,21 @@ import os
 import openmc.data
 
 
-# Get path to MCNP data
-parser = ArgumentParser()
+description = """
+Convert ENDF/B-VII.0 ACE data from the MCNP5/6 distribution into an HDF5 library
+that can be used by OpenMC. This assumes that you have a directory containing
+files named endf70a, endf70b, ..., endf70k, and endf70sab.
+
+"""
+
+class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+parser = argparse.ArgumentParser(
+    description=description,
+    formatter_class=CustomFormatter
+)
 parser.add_argument('-d', '--destination', default='mcnp_endfb70',
                     help='Directory to create new library in')
 parser.add_argument('mcnpdata', help='Directory containing endf70[a-k] and endf70sab')
diff --git a/scripts/openmc-convert-mcnp71-data b/scripts/openmc-convert-mcnp71-data
index 7e7fd923f..944095919 100755
--- a/scripts/openmc-convert-mcnp71-data
+++ b/scripts/openmc-convert-mcnp71-data
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 from __future__ import print_function
-from argparse import ArgumentParser
+import argparse
 from collections import defaultdict
 import glob
 import os
@@ -9,8 +9,21 @@ import os
 import openmc.data
 
 
-# Get path to MCNP data
-parser = ArgumentParser()
+description = """
+Convert ENDF/B-VII.1 ACE data from the MCNP6 distribution into an HDF5 library
+that can be used by OpenMC. This assumes that you have a directory containing
+subdirectories 'endf71x' and 'ENDF71SaB'.
+
+"""
+
+class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+parser = argparse.ArgumentParser(
+    description=description,
+    formatter_class=CustomFormatter
+)
 parser.add_argument('-d', '--destination', default='mcnp_endfb71',
                     help='Directory to create new library in')
 parser.add_argument('-f', '--fission_energy_release',
diff --git a/scripts/openmc-get-jeff-data b/scripts/openmc-get-jeff-data
index d0e5839b9..3166b3854 100755
--- a/scripts/openmc-get-jeff-data
+++ b/scripts/openmc-get-jeff-data
@@ -10,18 +10,17 @@ import glob
 import argparse
 from string import digits
 
+from six.moves import input
+from six.moves.urllib.request import urlopen
+
 import openmc.data
 
-try:
-    from urllib.request import urlopen
-except ImportError:
-    from urllib2 import urlopen
 
-if sys.version_info[0] < 3:
-    askuser = raw_input
-else:
-    askuser = input
+description = """
+Download JEFF 3.2 ACE data from OECD/NEA and convert it to a multi-temperature
+HDF5 library for use with OpenMC.
 
+"""
 
 download_warning = """
 WARNING: This script will download approximately 9 GB of data. Extracting and
@@ -32,14 +31,21 @@ space. Note that if you don't need all 11 temperatures, you can modify the
 Are you sure you want to continue? ([y]/n)
 """
 
-parser = argparse.ArgumentParser()
+class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+parser = argparse.ArgumentParser(
+    description=description,
+    formatter_class=CustomFormatter
+)
 parser.add_argument('-b', '--batch', action='store_true',
                     help='supresses standard in')
 parser.add_argument('-d', '--destination', default='jeff-3.2-hdf5',
                     help='Directory to create new library in')
 args = parser.parse_args()
 
-response = askuser(download_warning) if not args.batch else 'y'
+response = input(download_warning) if not args.batch else 'y'
 if response.lower().startswith('n'):
     sys.exit()
 
@@ -82,7 +88,7 @@ for f in files:
             files_complete.append(f)
             continue
         else:
-            overwrite = askuser('Overwrite {}? ([y]/n) '.format(f))
+            overwrite = input('Overwrite {}? ([y]/n) '.format(f))
             if overwrite.lower().startswith('n'):
                 continue
 
diff --git a/scripts/openmc-get-multipole-data b/scripts/openmc-get-multipole-data
index d51c196dc..bf0add284 100755
--- a/scripts/openmc-get-multipole-data
+++ b/scripts/openmc-get-multipole-data
@@ -10,18 +10,27 @@ import glob
 import hashlib
 import argparse
 
-parser = argparse.ArgumentParser()
+from six.moves import input
+from six.moves.urllib.request import urlopen
+
+
+description = """
+Download and extract windowed multipole data based on ENDF/B-VII.1.
+
+"""
+
+class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+parser = argparse.ArgumentParser(
+    description=description,
+    formatter_class=CustomFormatter
+)
 parser.add_argument('-b', '--batch', action='store_true',
                     help='supresses standard in')
 args = parser.parse_args()
 
-try:
-    from urllib.request import urlopen
-except ImportError:
-    from urllib2 import urlopen
-
-cwd = os.getcwd()
-sys.path.insert(0, os.path.join(cwd, '..'))
 
 baseUrl = 'https://github.com/smharper/windowed_multipole_library/blob/master/'
 files = ['multipole_lib.tar.gz?raw=true']
@@ -54,10 +63,7 @@ for f in files:
             filesComplete.append(fname)
             continue
         else:
-            if sys.version_info[0] < 3:
-                overwrite = raw_input('Overwrite {0}? ([y]/n) '.format(fname))
-            else:
-                overwrite = input('Overwrite {0}? ([y]/n) '.format(fname))
+            overwrite = input('Overwrite {0}? ([y]/n) '.format(fname))
             if overwrite.lower().startswith('n'):
                 continue
 
@@ -110,10 +116,7 @@ os.rmdir('wmp/multipole_lib')
 
 # Ask user to delete
 if not args.batch:
-    if sys.version_info[0] < 3:
-        response = raw_input('Delete *.tar.gz files? ([y]/n) ')
-    else:
-        response = input('Delete *.tar.gz files? ([y]/n) ')
+    response = input('Delete *.tar.gz files? ([y]/n) ')
 else:
     response = 'y'
 
diff --git a/scripts/openmc-get-nndc-data b/scripts/openmc-get-nndc-data
index 5bec3865e..5231b67ef 100755
--- a/scripts/openmc-get-nndc-data
+++ b/scripts/openmc-get-nndc-data
@@ -10,15 +10,28 @@ import glob
 import hashlib
 import argparse
 
-parser = argparse.ArgumentParser()
+from six.moves import input
+from six.moves.urllib.request import urlopen
+
+
+description = """
+Download ENDF/B-VII.1 ACE data from NNDC and convert it to an HDF5 library for
+use with OpenMC.
+
+"""
+
+class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+parser = argparse.ArgumentParser(
+    description=description,
+    formatter_class=CustomFormatter
+)
 parser.add_argument('-b', '--batch', action='store_true',
                     help='supresses standard in')
 args = parser.parse_args()
 
-try:
-    from urllib.request import urlopen
-except ImportError:
-    from urllib2 import urlopen
 
 baseUrl = 'http://www.nndc.bnl.gov/endf/b7.1/aceFiles/'
 files = ['ENDF-B-VII.1-neutron-293.6K.tar.gz',
@@ -50,10 +63,7 @@ for f in files:
             filesComplete.append(f)
             continue
         else:
-            if sys.version_info[0] < 3:
-                overwrite = raw_input('Overwrite {0}? ([y]/n) '.format(f))
-            else:
-                overwrite = input('Overwrite {0}? ([y]/n) '.format(f))
+            overwrite = input('Overwrite {0}? ([y]/n) '.format(f))
             if overwrite.lower().startswith('n'):
                 continue
 
@@ -115,10 +125,7 @@ with open(graphite, 'w') as fh:
 
 # Ask user to delete
 if not args.batch:
-    if sys.version_info[0] < 3:
-        response = raw_input('Delete *.tar.gz files? ([y]/n) ')
-    else:
-        response = input('Delete *.tar.gz files? ([y]/n) ')
+    response = input('Delete *.tar.gz files? ([y]/n) ')
 else:
     response = 'y'
 
@@ -134,10 +141,7 @@ if not response or response.lower().startswith('y'):
 
 # Ask user to convert
 if not args.batch:
-    if sys.version_info[0] < 3:
-        response = raw_input('Generate HDF5 library? ([y]/n) ')
-    else:
-        response = input('Generate HDF5 library? ([y]/n) ')
+    response = input('Generate HDF5 library? ([y]/n) ')
 else:
     response = 'y'
 
diff --git a/setup.py b/setup.py
index 4479bb82c..fd6a2e1a3 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@ kwargs = {'name': 'openmc',
 if have_setuptools:
     kwargs.update({
         # Required dependencies
-        'install_requires': ['numpy>=1.9', 'h5py', 'matplotlib'],
+        'install_requires': ['six', 'numpy>=1.9', 'h5py', 'matplotlib'],
 
         # Optional dependencies
         'extras_require': {