Years ago, I used to visit the Pizza House in Ann Arbor at 1 AM on weeknights. The fireplace was always going and the staff was always very friendly, and the bar! What can I say?
Pizza House has now opened shop in East Lansing, MI and recently doubled its size in that location. The menu is great, from Deep Dish Chicago-style Pizza to these huge pita sandwhiches called "Chipatis" .. Pizza House is a little slice of heaven.
I love the warm atmosphere, you wouldn't expect it in a strip-mall pizzaria. The pizza is fantastic, and the deep dish is sooo filling, you'll be done after one or two peices.
They also do delivery and as I mentioned before, they are open late! A must for near-campus businesses in this day and age.