Jim putting the stapler in a meatball is a callback to putting the stapler in jello
When Robert is looking at pictures of his house he's about to put on the market Jim initially jokes that it looks like the house from The Shining. Robert says he when he bought the house, he hoped it would be house like in Eyes Wide Shut. Both of the films referenced were directed by Stanley Kubrick
Meredith climbs out of the pool, soaking wet, and tells Val and Darryl they should try out the pool. Val hops up, then it goes to Darryl's talking head where we see a dry Meredith in the background, just sitting down soaking her feet on the side of the pool.