Grapevine Message Aggregator: finds & posts messages

From looking at the feeds, it seems it does a pretty good job of finding interesting projects:

http://twitter.com/#!/github_js http://twitter.com/#!/github_rb

What I find really neat about it, though, is that rather than just solve the case of aggregating and posting github repos referenced on twitter, it's designed to support other sources and destinations, by writing just a little bit of custom glue code.