Whack Attack is a game from the BBC that tests knowledge on Math, English or Science. It’s probably accessible to Intermediate English Language Learners.
The questions are good, though the game is a little weird. You’re given three answer choices. Each answer is color-coded, and in order to choose an answer, you have to “whack” the correctly-colored figure that keeps popping up.
I’ve placed the link on my website under Word and Video Games.