We never make plans for Saturday night. Since we want to make sure all the kids get showered and everything is ready to go for Sunday morning, we pretty much always keep it low key on Saturday nights. Our favorite night to socialize is Friday nights since we can stay up later, so we tend to hang out with friends on those nights.
I had been wanting to play games as a family more consistently when it hit me like a ton of bricks: we've already got a spot on the calendar for it! (Do you have "Where was my head?" moments as often as I do?)