...then you may as well be playing trains - especially if you make the train track cover the whole floor.
There is almost always some form of train track built on the floor. Anytime I mention that it is time to clean up downstairs, Peter announces, "But not my trains, right Mom?" He loves his trains and plays with them everyday. (After first asking if we can go to the zoo that day, of course.)
Today was a pretty special day because he got the huge track, and someone to play with him. It doesn't get much better than that. (Unless you also throw in a trip to the zoo.) Next year is going to be a bit of an adjustment for us when Duffy goes to school all day and doesn't get to stay home to play with Peter in the morning.
But today, at least, he is a pretty happy camper.