Name the Song
Assemble the players into a large group to challenge their musical ear. Play clips of a variety of songs for the players to try and identify. Use songs from the musical Mamma Mia as well as a few others from random movies and plays to throw them off. You could use instrumental versions of the songs to help disguise the identity or simply play very short clips of the music. Each child that correctly identifies the song wins a prize.
Find the Father
Incorporate the idea of a musical as well as the plot of the movie and play, Mamma Mia, into your entertainment. Select one person to play Sophie and have her leave the room. While she is gone, select one person from the group to be her father. When 'Sophie" returns she must question the individuals in the group to determine who is her father, but she cannot ask outright the question, "Are you my father?" Both the player playing Sophie as well as the group in their response must sing the questions and replies.
Who Said That?
Provide each player with a line from a Mamma Mia character. The players take turns reciting or singing their line. The rest of the group must guess which character delivered the line. If there is a tie, ask more questions about the specifics of the line, such as who the line was said to, or where the line was spoken.