A friend of mine (Matt Brender) started #commitmas last year as a way to give back to the open source community and to learn more about git/github. You can check out this link to the github repo about commitmas ( https://github.com/commitmas/30-days-of-commitmas-2015 ) or you take my synposis.
from Dec 1 to Jan 1, you make a commit to a git repo on github (same repo for the whole month). must do a commit every single day. should be a new repo for this #commitmas. can be on anything you want in any language (I suggest Xojo). must be open sourced (I suggest either BSD or MIT licenses). Now based on your experience level, he has some tasks that he would like you to accomplish in the month (it forces you to expand your git knowledge).
I have committed to Matt that I am going to do it this year. Not sure what I am going to do (yet). Once you are ready to commit to it, just fork the repo (above) and that lets him know that you are doing it.
if you have any questions, let me know!