It doesn't matter if we're with my family or my wife's family, when we get together we play board games. The Settlers of Catan is a favorite on my side, and Ticket to Ride is the favorite on Anna's side. (A new favorite that hasn't been introduced to the in-laws just yet is Power Grid.)

Ticket to Ride takes about 2 hours to play, and is one of those games that has the perfect blend of casual gameplay yet still requiring strategy and planning. Not too stressful but not at all boring.