My group interchanges DM-ing duties regularly, so we have 3 campaigns in progress now.
1) Return to the Temple of Elemental Evil: started 4, now at 13.
2) Homebrew campaign: started 4 (joined campaign later), now at 5
3) Greyhawk campaign - I'm DMing, so no PC for me, but the others started at 1 and are at 5.