I came accross this thing yesterday. http://www.gitlogs.com/

Find it pretty damn useful (and good looking).

GitHub has this functionality build in - Github Trending. You can search repositories, organizations, developers and filter them by language and time span.

Also Showcases is a great way to discover popular repositories organized by topics.

I always loved GitHub Trending and I recently released in the Play Store Top Github, a simple app for browsing GitHub trending repositories from Android (the app is also on GitHub).

I'm following this bot on Twitter: https://twitter.com/TrendingGithub

It polls every 30 minutes, and doesn't post duplicates in a short timeframe. You can read more about it here: github.com/andygrunwald/TrendingGithub

Not really a tool, but if Twitter is your thing it might fit in nicely.

I recently came across this app on Android called Github Trends - play.google.com/store/apps/details Have been using it regularly and it just fits my needs .

You can also star a repo locally without actually starring it in your profile , which is a huge win for me and i just absolutely love that feature .

Asked the developer if he has a donation page for just this feature , unfortunately not , but its a must have for me