The mentor summit is a great opportunity to meet developers from a wide
range of open source projects, it's probably one of the best
cross-sections of open source know-how you can find in a weekend. I can
only recommend going.

I can second that. Interesting open source developers from every place and every project. I've been to the summit last year. This year I didn't mentor, my time is limited and I just came back from the bay area, otherwise I'd have taken the opportunity to go to the mentor summit for sure :-)