YLLS! Or, put another way, Young Learners Love Spongebob!
So, why not give them a Spongebob themed reward when they have answered your question, or produced the language?
All they have to do is come up to the IWB and chose the Spongebob they want. When they touch it, they will be given points, if they select the correct Spongebob! The points appear in the box at the top of the screen, for everyone to see!