Copy the hooks into .git/hooks/ and make sure the script is executable.
You don't need to read the source.
-or-
You can clone this repo to ~/.githooks (git clone git://github.com/jhsu/githooks.git ~/.githooks) and add the ~/.githooks/prepare-commit-msg to your .git/hooks/ for some lulz
- Bro - add ", bro" to the end of git commit messages (depends on sed)
- Cowsay - cowsay commit messages (depends on cowsay)
- Fakecommit - "wait... didn't I just commit?"
- Iamyou - pre and post-commit hooks that changes your name to a random author
- Whatthecommit - prepends commit message with a nice commit message from whatthecommit.com (depends on curl)