Put all the ingredients but meatballs into the crockpot and mix well.
Add the meatballs and stir to coat well.
Put the crockpot on low and let cook for 4 hours on low (if you use thawed meatballs, it'll only take a couple of hours in the crockpot, instead).
Serve, standing back so you don't get trampled by the rush of the crowd.
Note: We've tried other preserves and jam than grape jelly, but the sauce simply didn't taste as good; we're sticking with plain, old grape jelly from now on and will be happy with it. Also, you can use Lil Smokies or sliced smoked sausage instead of the meatballs - a lot of folks use the same sauce for either and both ways are tasty! :)
Note 2: the above makes a lot of sauce, a good deal of which will be left over when the meatballs have been eaten. I've found that having a *lot* of sauce is of real benefit when making meatballs in the crockpot - the meat remains nice and moist.