When I first came across the name of this holiday drink, I immediately thought of the animated cat and mouse I watched as a child. Was I suprised when I found out there was no relationship to the lovable cartoon characters! Tom and Jerry is a Christmas drink that originated in Europe in the 1820's. A sports writer named Pierce Egan wrote a book entitled Life in London, or The Day and Night Scenes of Jerry Hawthorn Esq. and his Elegant Friend Corinthian Tom. To promote his book, he developed a variation on eggnog, giving it a bigger kick with the additon of rum. He called his drink the Tom and Jerry. There are other theories on the drink's origin, but this is the most accepted.
Many glass manufacturers have produced sets specifically for Tom and Jerry's consisting of a large punchbowl and matching mugs. You'll often find the cups, but it's much more difficult to find the bowl. Here's a recipe from About.com if you'd like to try it yourself.