Bring 6-10 different songs with you to the group gathering (make sure they are fairly popular songs). If possible, burn all of these songs together onto one CD.
Once the group is ready, start the first song and let it play for about 5 seconds. See if anyone can guess the title of the song. If nobody gets it at first, play the song again and let it run for 10 seconds. Repeat this activity for the rest of your songs, and keep a tally of who guesses each one correctly. At the end, give a new CD as a gift to the person who guessed the most titles.
Listen carefully while you play this game. You'll learn a lot about the tastes of those who choose to participate!
