The iPad we got over the holidays has opened a Pandora's box of possibilities. There are sources for videos, audio, games, lessons, etc. DS is trying out a couple of different apps a day, settling into a couple (e.g. King of Math) and moving onto something else in other cases. And it isn't just math; last night we were watching a fairly deep three minute video on RNA replication, and he didn't want to head to storytime until he had finished the quiz on the video.