Just finished a small personal project: Github Watchlist, a search engine that allows me to search into all my watched repositories on Github, with full-text indexing of all the README files of the projects. Here is an example query: http://watchlist.crohr.me/crohr?q=rest+http.
I created this because I find the Github search engine to be mostly useless. Sometimes I know I favorited (watched) a project, but can’t remember the name. And it seems like Github’s engine does not search into the READMEs, only the project’s descriptions (at their scale, I guess they have good reasons to do this?). Which leads to average results (at least in my case).
This project is mainly targeted at myself, but if you’re interested you can try to create your own search engine.