I have been a proponent of pre-commit hooks for a very long time. After doing some searching, I found this lovely gem. It consists of a bunch of checks before you commit your code into the repository. A couple of my favorites:

• php - Runs a PHP syntax check on all PHP files
• merge_conflict - Makes sure you aren’t about to commit merge conflicts (you know, >>>>>>>> HEAD, stuff like that)
• ruby_symbol_hashrockets - Prevents you from committing old-style Ruby hashes ( :hello => 'there' )

And much more. Highly recommended!