I would like to suggest that folks consider working on git itself. The git mailing list is very friendly and supportive and you will be making a valuable contribution to the git community. You'll also have an opportunity to brush up your C skills with guidance from some excellent C hackers.

If you aren't a C coder, you can help to improve the documentation (really, just pick a man page, there are many that can use improving). Or, look at it as an opportunity to learn C -- some parts of git are quite advanced, but there's also lots of areas that are easy to work on.

See the git wiki for some areas that can use love:

https://git.wiki.kernel.org/index.php/Janitor

https://git.wiki.kernel.org/index.php/ToDo

https://git.wiki.kernel.org/index.php/Wishlist

(Sadly the wiki is down right now, so please paste those links into google and click the cached link.)

So go on, get yourself listed on http://git-scm.com/about

:)