Habari is a great open-source project to contribute to if you want to give back to the community and have a sense of accomplishment. If you find a ticket you want to work on, simply create a patch, upload it and get someone from the community to review it. My patch was committed to the source control repository in under 24 hours!
The project also has a very active IRC channel with a community willing to listen, and a bot that is quite useful (leave a message for an offline user, get a link to a page for a specific topic, ...).