Okay, so I have no idea how I missed these. So far, I've seen Statler & Waldorf, Sam the Eagle, Gonzo, Beaker, and the Sweedish Chef (featuring Beaker). I have to say, my favorite part is reading the descriptions on the Beaker and Chef videos. (The videos are also embed after the break, if you want them all in one place.)
Meh
Stars & Stripes FOREVER!
Classical Chicken
Ode To Joy
Habanera