Carol,
Here is a recipe that gets raves. It is more complicated than some of the others but it has a great depth of flavor.

Raspberry Enlightenment Meatballs
2 to 3 pounds frozen meatballs
1 jar (9.8 ounces) Penzey's Raspberry Enlightenment Sauce
26 oz of sweet and sour sauce
1 jar (12 ounces) orange marmalade
1 bottle or jar 8 – 12 oz. Cranberry Honey mustard
1/2 cup (or to taste) chili garlic sauce

In a slow cooker, place the meatballs. Add all remaining ingredients and stir to combine. Cook on high for 2 hours, reduce the heat and cook until the meatballs are heated through, stirring occasionally

Makes about 90 meatballs
Preparation time: 15 minutes
Total time: 2 hours 15 minutes
NOTES: Penzeys’ Raspberry Enlightenment Sauce is available from their stores in major urban areas or from penzeys.com. In a pinch I’ve used seedless raspberry jam. Sweet and sour sauce varies widely in quality. Try to find a good tasting one. If you find 3 jars and it’s a bit more or less than 26 oz., don’t worry. This is not baking and the volume of ingredients is not crucial. Start with less of the Chili garlic sauce and add to taste. If you use Sambal oelek, it can get quite spicy!