#1day1patch: let's all contribute to a better Drupal contrib. universe
The idea comes from a simple statement: if every Drupal developer was giving even only a few minutes every day to provide even the simplest patch on any contributed module shared on Drupal.org, that would benefit to all.
This is one of the basic principles of open-source development, but it's good to remember it sometimes: an open-source software is free to use, but also free to improve, and share.
By fixing an issue (even the most trivial one) and providing a patch to the community, you help other users of course, that may have the same issue as you, and find in your intervention a solution to your problem, but you will also help the maintainers team, freeing their time for more complicated issues, or improvements. It will also, and you should think about it, help yourself, by freeing you from that custom code you introduced in Drupal, that would prevent you to update your site easily, and would ask for maintenance (because you may introduce bugs, conflicts, side effects). By contributing this code, you ensure that it will have maintainers, and that many users will use it, report bugs they find, and maybe patch them!
You got it (you probably already knew it), contributing is good.
So what's up with #1day1patch, isn't everybody already involved, and patching Drupal? Yes and no. It can be hard sometimes to find the motivation, or the time to search for an issue, and fix it. Or maybe you didn't even have any issue today and don't find the urge to contribute a patch. #1day1patch is there to remind you that every day modules are waiting to be fixed, and to encourage to contribute a patch, even the most little one, to the community, by emphasizing team membership sense, challenge and showing people you did your part too. Every time you help improving a contributed module on Drupal.org, tweet about it, and attach the #1day1patch hashtag. If you're curious and clicked on the hashtag, you saw that many people are already participating, and that the number grows everyday. And it's already working: here are lists of fixed and closed issues due to this initiative, while list of submitted patches grows everyday.
Any help is welcome, so feel free to join us, tweet about it, submit your patches, and show Drupal contrib some love!
If you don't know where to start, you can start by having a look to Drupal's Contribute to development documentation, then next, if you have no idea what to patch, you can try Drupal's contrib bug bingo (which needs some improvements though).