Quia.com

At quia.com, you can create simple games in disciplines as far ranging as chemistry and music. I just played hangman showing my knowledge of technology terms, matched chemistry equipment to uses, and researched the eruption of Mount Vesuvius as part of a scavenger hunt. Although targeted primarily at high school students, Quia lets you create your own games at any level--I'm thinking about using it in my undergraduate course next semester to help my students learn about IT laws, something that they've had difficulty with in the past.