The two main actors from Bones (Emily Deschanel and David Boreanaz) were in the audience.
There was a guy who kept booing really loudly throughout the night. Eventually (after Siobhan's performance) Simon said "who are you? Stand up". He showed himself, and then went on stage to give Siobhan a hug.
As part of their video clips, the other contestants shared some information about the contestant about to perform.
At the beginning of the episode, after the credits, they switch to a camera, but it clearly wasn't in the right position as it looked like the person operating it was walking with it and not aiming at anything specific.
This is a 2 hour episode
Paul McCartney sent in a message to wish the Idols good luck.
Aaron Kelly - The Long and Winding Road
Andrew Garcia - Can't Buy Me Love
Casey James - Jealous Guy
Crystal Bowersox - Come Together
Katie Stevens - Let It Be
Lee Dewyze - Hey Jude
Michael Lynche - Eleanor Rigby
Siobhan Magnus - Across the Universe
Tim Urban - All My Loving