Take a look at the games at the Learning Games Network.
Also, create a treasure hunt game, using QR codes. See teacher instructions.
See sample quiz questions, made using CREATE - FORM in Google Drive. When you make a quiz in Google Drive, your students' answers are collated and you can create temporary groups to tackle misunderstandings revealed by the quiz answers. In your school setting, place posters with QR codes around the school and students can follow clues and answer riddles, to find real treasure.