...is chase.
It doesn't need to involve someone actually chasing him, for him to THINK someone is chasing him and run away. For example, Ben the dog does NOT chase Tucker. Ever. But Tucker gets a lot of entertainment out of their make-believe chase scenes. This is how they go: Ben moves vaguely in Tucker's direction. Tucker giggles excitedly and runs away. Ben sees Tucker giggling and runs in the opposite direction. Tucker gets even more excited.
However, I do have the opportunity of playing real chase games with Tucker regularly. Our downstairs rooms form a vague oval so you can run from the family room to the dining room to my office through the bathroom to the sunroom to the kitchen and be back where you started. When I was on the phone with my mom the other day, Tucker and I spent half the conversation doing loops around our downstairs "track." We went around at least 5, maybe 10 times. We usually have to do at least one loop before I can catch him and bring him upstairs for a diaper change.
He is also getting adept at selecting things that he can't have, in order to get me to chase him. I was installing some more baby latches on a few cabinets today, and somehow Tucker managed to abscond with the power drill two separate times, and the scissors once. He didn't even protest when the items were (quickly) taken away--he just wanted the thrill of the mommy chase.