In addition to all these other brilliant ideas, I'd like to point out that depending on the grain bill, you can make people treats as well as dog treats. I make a spent grain sour dough loaf that is really delicious as a breakfast bread. If you have a flower mill, you can let the grains dry and mill them with your wheat to make multi-grain flower (although not as rich after the mash. Still delicious.) And I make granola bars for my girlfriend and I using the spent grains, some honey, peanut butter, and some fresh oats. Lay them out on a baking sheet and cook them just long enough for everything to be cohesive.
I not everyone will agree, but I think the toasty maltiness really goes well in alot of baked goods, and I'm always experimenting with new ones. There are several recipes available online, but I'd say anything that has flower or grain in it, you can mix in some spent grain for flavor and texture.