If you have ever played Head Banz, or Heads Up (as seen on Ellen) you will love this free app. ($0.99 if you want it without adds). Cherades. You hold the tablet to your forehead facing out, your partner gives you clues to say the word. Tilt the tablet up over your head if you pass and down to your lap if you guess the word. See how many you can do in a certain amount of time. I haven't even got to the cool part. The very last category folder is Custom...now your options are endless.
I have been trying to play this game with my grade 4s using cards with names of quadrilaterals...no more cards! I will also use it to practice mental math; put in the answer and the clue needs to be addition questions, or subtraction, or multiplication..you get the idea.