What is the best way to re-serve day old meat balls? I've noticed that meatballs are one type of food that often tastes much better the next day.  So whenever I make meatballs, I make lots of extras and put them in my fridge to allow the flavors to "develop".

However, when I warm the meatballs up in the microwave they sometimes get dry or have slightly tough and rubbery spots -- especially on outside edges.

What is the best technique to re-warm / re-serve meatballs that you have made the previous day (or a couple days prior) so they stay moist and delicious?
My preferred method by far would be heating them in a pot along with some kind of sauce.

Failing that, I think I might try putting them in a tightly covered pot in the oven along with just a little water (just a tablespoon or so)--that would gently heat them and also keep them moist.