I LOVE Liberty Park. It's one of the things I like most about living downtown. It's so big that we can almost always find a spot to let the dog off the leash and have our own space.
Zach always plays this game where he tries to make big moves without disturbing Tyke. I don't know how this game originated and it has many different variations, including trying to sit on him, trying to dance with him, etc. I guess it's good training for when the kids get bigger. But the good old standby is when he stands on things and attempts to leap over him.