I've found one of the best ways to do the "stubmleupon" concept is to follow dozens of devs who star interesting repos (sometimes solely for that reason) and check your news stream often. I follow devs from a wide variety of backgrounds, which yields numerous libraries that I might not otherwise be aware of (and sometimes months ahead of HN exposure). One of the best things I've done with my GitHub account.
A solid example is: https://github.com/fogus