Easy answer would be "play games, stupid". But as our consoles do more and more besides just play games, it's interesting to see exactly what we're doing with them (and for how long) when we're not killing/racing/solving something.
Research firm Nielsen conducted a nation-wide survey in October, aimed at determining what percentage of time people use a game console for gaming as opposed to other stuff, like watching movies or doing a little social networking.
Some of the key findings were that the PlayStation 3 gets a serious workout as a DVD/Blu-Ray player, with 72% of the console's owners using it for that purpose as opposed to 43% of Xbox 360 users.
Also interesting is some raw usage figures, showing that Xbox 360 owners use their machines for more hours a week than PS3 owners use theirs, and 2-4 times as many as Wii owners, who on average spend only an hour and a half each week using Nintendo's console.
You can see a more detailed break-down of the figures in the gallery to your left.
Game Consoles Edge Closer to Serving as Entertainment Hubs [Nielsen]