For those of you going to UCA, they will actually be hosting a scavenger hunt of their own. If you participate, you get a UCA pin and a possiblity to win bigger prizes.
Also, for ANY competition at disney there are so many great photo ops at the parks! Heart of Texas Cheer did one last year at worlds and it looked so fun! They have a list of what they used here:
Heart of Texas Cheer & Dance - Photos
Some additional disney ones could be:
-picture of floating pennies on Tower of Terror (put a penny on your knee before the ride starts, and it will float on the drops)
-picture with the giant megaphone at Allstar Sports Resort
-picture with the ESPN globe statue at Wide World of Sports
-picture with everyone wearing princess crowns
-picture with a mickey mouse shaped food product
-getting "chomped" by the dinosaur head statue in the Dinosaur ride line
-being an astronaut on mission space
-hitting your best rock n roll pose at or on Rockin' Rollercoaster
-BONUS: a picture of someone getting chosen to participate in a show (has to be actually chosen, no cheating!)
-Getting a picture with someone's look alike Disney character
-Wearing 3D glasses at either Phillarmagic, It's a Bugs Life, Muppets 3D or Honey I Shrunk the Audience
-Group picture with fireworks in the background