Hymn a Happy Tune
(courtesy of the Lake Oswego Oregon Stake, and shared by Bobbie Poppleton)

materials: none

Announce to the class that you are thinking of a song (hymn or Primary song) that fits the theme that your class has been discussing. Tell them if anyone can guess it in 5 notes, they're "it". Then just hum those first five notes.
Don't sing the words. The first student to guess the song correctly is "it" and gets to pick the next song and hum it. If no one guesses it anfter 5 notes, try 10. If they still don't get it, give them other hints (the title has 2 words, or it begins with a "G" or it's about temples).