My favorite part is the Grocery store and the Pizza Parlor and the Fishing Pond and the Bank and..... well, you get the point - Its ALL fun!
Morty's favorite part is the mechanic slide board thingy that goes under the car... I dont know the real name for it but you get the idea. He just lays down and has mom slide him back and forth, back and forth until she tells him its time to go home.