I do a whole chicken in the crock pot by putting a peeled onion in the cavity and pouring a beer over the top. Cook for 7-8 hours (depending on size) on low. - You can also use a lemon or lime instead of the onion.
My SIL recently gave me one for beef tips, too. - Italian dressing, brown sugar, and garlic. I haven't tried it yet, but it sounds yummy!