High school or College/University?
With a dev. board there is a lot you can do especially with all the memory available on that board (I'm stuck to onchip memory only with my board at home). I have lots of ideas floating around in my head just need the time to do them, but I wouldn't recommend those if they are a beginner (I was going to create a DSP system to do fast signal processing and compression on video and audio signals).
When I was in high school I made a circuit that interfaced with a PC and I made a real........... kindergardenish looking GUI to control it. My hardware interfaced with analog parts to control a train set so I could automate switching tracks, bypassing parts of the track that were blocked by an object, direction of the train, lighting in the houses, etc..... And I did this with descrete TTL parts (yep that's right TTL, so this thing needed a power bar to run) so with an FPGA this should be nicer (not easier but nicer).
If you don't mind your board getting beat up, maybe a battle bot would be a cool project (that is something those of us at my University always wanted to do, but didn't have time to do.... that and we were lazy lol).
Sounds like fun, hope the student likes it