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Kai Hansen qualified on the first two Gamma Ray live videotapes (later released on DVD) where Ralf Scheepers was singing, giving Kai free rein to bounce around like he's high on crystal meth, grin maniacally at the camera, and generally act goofy and silly. Unfortunately he's much more restrained these days.
Brendon Urie in the video for "Nine In The Afternoon". He was basically running around in pajamas for a good portion of the video and kept picking up random objects like an alarm clock and a vacuum.
The band Structures' drummer. Seriously look at him! If you don't want to look, though, just know that every time he drums he has a massive smile on his face and puts everything he has into it without ever getting tired.
Several 'trouser roles' in opera—the character is a boy/young man, sung by a soprano—qualify.
Kevin Talley is notoriously outgoing and hyperactive in person, in addition to having a highly energetic and theatrical playing style.