I created this because I was frustrated with losing interesting events happening on GitHub (GitHub doesn't send you emails when somebody stars or forks one of your repositories or follows/unfollows you).
It started out as a simple script that sent me an email, but then I thought that maybe this was something that other people could find useful, so I turned it into a website, picking up ruby again after a long time in the process.
You can find the code on GitHub: https://github.com/andreausu/github-notifier (it's not pretty, I know)