diff --git a/tools/big_red_button.py b/tools/big_red_button.py
index c0968aefad1ecc8ad7669557865a09336bfb36d9..3136a24db8c252e921f861f29dd05c7c6a1d9a5c 100644
--- a/tools/big_red_button.py
+++ b/tools/big_red_button.py
@@ -4,52 +4,82 @@
 
 # Make a commit, upload it, land it.
 
+# Useful links:
+# http://stackoverflow.com/questions/14665518/api-to-automatically-upload-apk-to-google-play
+# https://developers.google.com/resources/api-libraries/documentation/androidpublisher/v2/python/latest/androidpublisher_v2.edits.apks.html
+
+import argparse
 import os
 import subprocess
 
+DEFAULT_MOJO_ROOT = '/src/mojo/src'
+DEFAULT_SKY_SDK_ROOT = '/src/sky_sdk'
+DEFAULT_DEMO_SITE_ROOT = '/src/domokit.github.io'
+
 def run(cwd, args):
     print 'RUNNING:', ' '.join(args), 'IN:', cwd
     subprocess.check_call(args, cwd=cwd)
 
-# Input paths:
-# FIXME: These could be args?
-MOJO_ROOT = '/src/mojo/src'
-SKY_SDK_ROOT = '/src/sky_sdk'
-DEMO_SITE_ROOT = '/src/domokit.github.io'
-
-# Derived paths:
-DART_SDK_ROOT = os.path.join(MOJO_ROOT, 'third_party/dart-sdk/dart-sdk')
-PUB_PATH = os.path.join(DART_SDK_ROOT, 'bin/pub')
-PACKAGES_ROOT = os.path.join(SKY_SDK_ROOT, 'packages')
-
-
-run(MOJO_ROOT, ['git', 'pull', '--rebase'])
-run(MOJO_ROOT, ['gclient', 'sync'])
-run(MOJO_ROOT, ['mojo/tools/mojob.py', 'gn', '--android', '--release'])
-run(MOJO_ROOT, ['mojo/tools/mojob.py', 'build', '--android', '--release'])
-# Run tests?
-
-run(SKY_SDK_ROOT, ['git', 'reset', '--hard', 'origin/master'])
-run(MOJO_ROOT, [
-    'sky/tools/deploy_sdk.py',
-    '--non-interactive',
-    '--commit',
-    SKY_SDK_ROOT
-])
-# tag for version?
-
-run(DEMO_SITE_ROOT, ['git', 'reset', '--hard', 'origin/master'])
-run(MOJO_ROOT, ['mojo/tools/deploy_domokit_site.py', DEMO_SITE_ROOT])
-# tag for version?
-
-for package in os.listdir(PACKAGES_ROOT):
-    package_path = os.path.join(PACKAGES_ROOT, package)
-    if not os.path.isdir(package_path):
-        continue
-    run(package_path, [PUB_PATH, 'publish', '--force'])
-
-run(SKY_SDK_ROOT, ['git', 'push'])
-run(DEMO_SITE_ROOT, ['git', 'push'])
 
-# http://stackoverflow.com/questions/14665518/api-to-automatically-upload-apk-to-google-play
-# https://developers.google.com/resources/api-libraries/documentation/androidpublisher/v2/python/latest/androidpublisher_v2.edits.apks.html
\ No newline at end of file
+def main():
+    parser = argparse.ArgumentParser(description='Deploy!')
+    parser.add_argument('--mojo-root',
+                        action='store',
+                        type=str,
+                        metavar='mojo_root',
+                        help='Path to mojo/src',
+                        default=DEFAULT_MOJO_ROOT)
+    parser.add_argument('--sky-sdk-root',
+                        action='store',
+                        type=str,
+                        metavar='sky_sdk_root',
+                        help='Path to sky_sdk',
+                        default=DEFAULT_SKY_SDK_ROOT)
+    parser.add_argument('--demo-site-root',
+                        action='store',
+                        type=str,
+                        metavar='demo_site_root',
+                        help='Path to domokit.github.io',
+                        default=DEFAULT_DEMO_SITE_ROOT)
+    args = parser.parse_args()
+
+    mojo_root = args.mojo_root
+    sky_sdk_root = args.sky_sdk_root
+    demo_site_root = args.demo_site_root
+
+    # Derived paths:
+    dart_sdk_root = os.path.join(mojo_root, 'third_party/dart-sdk/dart-sdk')
+    pub_path = os.path.join(dart_sdk_root, 'bin/pub')
+    packages_root = os.path.join(sky_sdk_root, 'packages')
+
+    run(mojo_root, ['git', 'pull', '--rebase'])
+    run(mojo_root, ['gclient', 'sync'])
+    run(mojo_root, ['mojo/tools/mojob.py', 'gn', '--android', '--release'])
+    run(mojo_root, ['mojo/tools/mojob.py', 'build', '--android', '--release'])
+    # Run tests?
+
+    run(sky_sdk_root, ['git', 'reset', '--hard', 'origin/master'])
+    run(mojo_root, [
+        'sky/tools/deploy_sdk.py',
+        '--non-interactive',
+        '--commit',
+        sky_sdk_root
+    ])
+    # tag for version?
+
+    run(demo_site_root, ['git', 'reset', '--hard', 'origin/master'])
+    run(mojo_root, ['mojo/tools/deploy_domokit_site.py', demo_site_root])
+    # tag for version?
+
+    for package in os.listdir(packages_root):
+        package_path = os.path.join(packages_root, package)
+        if not os.path.isdir(package_path):
+            continue
+        run(package_path, [pub_path, 'publish', '--force'])
+
+    run(sky_sdk_root, ['git', 'push'])
+    run(demo_site_root, ['git', 'push'])
+
+
+if __name__ == '__main__':
+    sys.exit(main())
\ No newline at end of file