Type in any Christmas song and watch the little chins. Also, type in any non-Christmas songs (I typed in 'Happy Birthday') You'll get a kick out of the response. One of the funniest I typed in was 'Jingle Bell Rock'... They forget the words half way through. Don't forget to end with "We Wish You a Merry Christmas".
http://www.sundog.net/carolofthechins/flash/card.swf
http://www.sundog.net/carolofthechins/flash/card.swf