We have a pop up tent/tunnel/ball pit in the living room, along with a tub of toys for C&C to play with while I'm cooking dinner or for just any time we aren't up in the play room since they can't climb up and down the stairs by themselves just yet. They loved to go in the tent and sit there and wait for us to say "where's Chloe?" or "Where's Connor?" and then they pop their heads out and we say "There she/he is!" and they think it's hilarious.
Chloe gets the biggest kick out of it.