We use our crockpots year round, but especially in the winter. We love to cut up a beef round steak into small-medium sized pieces and throw it in with chopped onion and a couple or three cans of cream of mushroom soup and water, enough to cover the meat. Really love it served open-face with garlic mashed potatoes! We do the same with pork chops, chicken, tame rabbit, squirrel, venison, etc. Outside of organs, I can't think of anything I wouldn't like fixed like that!
Edited to add water to the canned soup. It will thin down considerably as it cooks, so I only add about a half can of water to a can of soup. Wife likes it thinner and uses a whole can of water - still good, just have to have more biscuits to sop up the extra gravy!
Other favorites are:
swiss steak
pork chops and Spanish (Tex-Mex) rice
stuffed bell peppers
roast, carrots & potatoes