This one calls for three whole ingredients. I'd advise making a double recipe, because they'll go FAST.
In a crock pot, combine one bag of frozen Italian-style meatballs, 12 ounces of grape jelly (cheap is fine) and a 10-ounce bottle of chili sauce (found with the ketchup in most grocery stores).
Turn the crock pot on low and stir occasionally until jelly is melted and combined with the chili sauce. The sweet-spicy flavor is addictive. Feel free to make the recipe sound much more complex than it is when you tell your guests about it.