Harold's playing a Fisher-Price sports video game, one where he has to swat at virtual tennis balls with letters on them. He's doing great; his hand eye coordination is superb.
Here's the funny part, indicative of what crazy stuff kids come up with, the stuff that makes TV shows a hit. He's swatting at the tennis balls, and he's proud of a couple of particularly difficult swings. He turns to his mom and says, "I got a little T and A!"