I love scavenger hunts, but I'm not sure I understand what you are looking for.
Do you need a list of things for the kids to find? I assume that you want them to find actual things (rather than taking pictures with Polaroid cameras) without them having to buy them? Do you want the things to be food-related?
What does "14 day/14th birthday" mean? And what does "10/10 for the class" mean?
Sorry about not interpreting the shorthand, but I'm new here.
10 girls, 10 boys. he'll be 14, on the 14th...
I don't care what they scavenger hunt for, the pizza idea is good, but since they don't drive I don't know what they'll find in the neighborhood, so I'm thinking things- but I was looking for some sort of theme, or at least an idea of what sorts of things they need to hunt for. sorry for being clear as mud.