Meatball sauce in crockpot....?

OK, we are having an Open House tomorrow and some important people will be attending. We will have little 'bites' throughout the office for people to munch on and one will be meat (in crock pot to keep warm). I need some FABULOUS sauce recipes that will make a great impression!! I don't want dipping sauces - I need the sauces that the meat can simmer in. Preferably something sweet/sour or spicy. We were thinking of Curry or ???? NOT plain BBQ Sauce.