Team Hilario is a fake band that Joe Jonas, Greg Garbo and former drummer Alex Noyes created along with Nick Jonas as the "Coach" (a.k.a. Nick in a 'The Rock' mask.)
Team Hilario is really just one giant inside joke between the Jonas Brothers and their band. They "performed" the song "I Believe I Can Fly" (originally by R Kelly) at one of their Jonas Brothers concerts in summer of 2006.
In some older pictures, you might even see Nick wearing a Team Hilario shirt. Again, just a big inside joke, haha.
Members
According to the official Myspace page, there are 4 members of Team Hilario. Coach Hilario, #1, #2, and, #3.
In addition, they list "John Lloyd Taylor" (their guitarist) as the "General Manager" and someone called "'Towel Boy' (formerly known as 'water boy')" who many speculate to be Kevin.
YouTube
Several videos of Team Hilario's performance of "I Believe I Can Fly" are still available on Youtube today (see below.)