Using your ice cream machine to make Coke slushies...I'm thinkin' Dr. Pepper slushies for me, and Sprite slushies for J, mmm! Check it out here (it also tells you how to make frozen hot chocolate..hmm).
(image from real simple article)
The next one that I thought looked interesting for sure was: grilled cheese in your waffle iron. My husband thought it sounded gross, but he also thought you used waffle BATTER. Um. No. The instructions can be found here, although I think there are a few typos in the 'how-to'. If you read it, it doesn't quite make sense, but it's pretty basic. Make sandwich ---> put in iron. It's not rocket science.
Anyways, I definitely want to try the grilled cheese.