Concert with the Most Bands? (read details pls)?

Question

I just read an article in Rolling Stones Magazine on the BONNAROO concert which (and I might have read this wrong) 150 different artists? Is that concert considered one with the most artists, or are there other events with as many bands as that? And does it happen every year?

Answer 1

Bonnaroo happens every year, and I think they pull 150 or so acts every year.  There are festivals all over the country all summer, but I think that's the biggest.

Answer 2

I don't know how many artists or bands are in it, but I know summerfest is pretty huge.

http://en.wikipedia.org/wiki/Summerfest