Does the GIL Make Your Ruby Code Thread-Safe? - This is a guest post by Jesse Storimer, esteemed author of Working with Unix Processes, Working with TCP Sockets and Working with Ruby Threads. There are...
#1 MerbCamp - Yes, all merbists have seen it.
#2 Merbunity - It's maintained by hassox!
#3 Atlanta ruby user - I found this site recently. I think it's worth to see.
#4 Merb Dependencies and Bundler - by
#5 peepcode (well, not free. but it's 9$) - The screencast was recorded on merb 0.9 but it still is a good one.
And there are good tutorials.