I think it would be really interesting to just enter in a bunch of random grains, ferment the resulting wort, and see what it turns out to be. At that point I think that would be busting into the realm of random hybrid beers which could be good or bad depending on what you use. The other thing is that you have to make sure you have enough grain with the right amount of components to foster a healthy fermentation. You need enough grains with fermentable sugars, dextrins, proteins, and diastatic enzymes like alpha/beta-amylase. If you dont get a good balance then you wont have healthy fermentations and will just be making exspensive drain cleaners. If you want to experiment just google search a grain you have, say 6 row pale malt, and what beers you can make with it. For example search "beer recipes 6 row pale malt" and you might get some good results. Other then that I would just ask around on the forums or get some kind of brewing software like beersmith 2. Cheers, and good luck.
"Relax, dont worry, have a homebrew." -Charlie Papazian
"A friend with yeast is a friend indeed."
"Beer is proof that God loves us and wants us to be happy." -Benjamin Franklin