Mike Gordon first sat in with Sound Tribe Sector 9 at the second annual Bonnaroo in 2003. We wandered over to Sector 9, Gordon told Jambands.com at the time. I had never seen them before, but I was really into it. We left before the encore, but then it occurred to me that maybe I could play, so I ran back. Last night, Gordon performed with the group once again at South Burlington, VTs Higher Ground. An off-night from their current tour with Umphreys McGee, the members of STS9 invited Gordon out for an improvisational segment a few songs into the groups second set. Oddly enough, STS9 has yet to collaborate with Umphreys McGee during their joint tour, which will continue this evening at New Yorks Roseland Ballroom. For more on STS9, please read our recent site interview with bassist David Murphy.