Sing or Dare: "Sing" cards like "sing [the song] while marching the beat" or "sing the song, but buzz all the words 'the'." "Dare" cards like "Name everyone in the room" or "Hug the teacher." (I think I might change the dares to musical things like "sightread a simple song" or "play the melody on the xylophone.")
Rhythm Game: "Busted!" Pull a stick from the jar, clap its rhythm. Pull another stick, clap both rhythms. Continue cumulatively. If you pull the "busted" stick, you have to put all yours back. Kid with most at the end wins.