My roommate Tim (his LinkedIn) and I decided to start challenging ourselves with little applications we could develop.
The first thing we thought of was a way to decorate your GitHub activity board, example below:
The idea being that you could just draw or type (or both) anything that you wanted to on a canvas that represented your github activity board, and with one simple script you could create the required commits and upload that new repo to your GitHub.
This is thanks to a feature/flaw in git that allows you to create commits (even empty commits) with any date attached. Therefore, all we need to do to generate a cute little activity graph is to simply work out the date ranges required, how many commits to make each day, and to generate a script that allows the user to do this.
Made open source under the WTFPL licence.