Getting ready to play Wii games / Play station / Xbox games together. Putting in the game dvd, plugging in Wii remotes ... it might even stretch to setting up suitable food: bowl of popcorn, drinks etc.
Similar to 'tool up' when getting ready to do some serious DIY.
Robert, are we playing Mario Kart of Lego Star Wars?
Let's play Mario Kart dad.
Ok, let's Game up then.