How much time do college students spend playing video games? I did some quick Googling this morning and was unable to come up with any recent numbers. (Can you do any better?)
What I did find was that:
According to a Harris Interactive 2007 survey,  the average teen boy spends 18 hours per week playing video games, 10 more hours than his female counterparts.
--97% of teens, age 12 to 17, play computer games - encompassing console, Web or portable games.
--86% of teens play console games such as XBox, Playstation or Wii.
The last study to focus on college students that I could find is a 2003 Pew Internet & American Life report, Let the Games Begin: Gaming Technology and Entertainment Among College Students. 
My guess is that a significant proportion of our college students spend more time playing video games then studying, sleeping, eating, going to class, and perhaps breathing.
As someone who makes his living in learning technology I applaud this trend, and as a parent I see it as my duty to contribute to the video gaming habits of our next generation of students. With this goal in mind, I set out with my older (7th grade) daughter to our local GameStop to pick out a new game for our family Wii.
I highly recommend a pilgrimage to GameStop as the fastest route to conduct a little ethnographic observation amongst our future scholars. GameStop is to today's teen boy what the record store, comic shop, and arcade was to my generation. Video games, particular console games, have replaced baseball cards and Dungeons and Dragons. On any given Saturday night you can find clumps of teenage boys hanging out, exchanging used games for other used games, playing demo games, and engaged in deep, learned passionate debate. Best graphics and game play: Halo 3 or Call of Duty 4? Most skill required: Need for Speed or Guild Wars? Guitar Hero vs. Rock Band.
I was happy to bring my 12 year old to GameStop so she could get a glimpse of the teenage boy in his natural environment. She was eager to go home after we picked up Shaun White Snowboarding for the Wii balance board, overriding my desire to hang out and chat with the employees (teen boys indistinguishable from the patrons in their piercings, black concert t-shirts and baggy pants).
On the drive home we discussed GameStop culture, and how important it is for everyone to have a place to go where we can find people who share our passions and predilections. We agreed that the GameStops of the world, while seemingly profitable today, feel like an anachronism in a world where digital entertainment (music, movies, TV) are purchased by the download. How long can video games hold out as bits and bytes that are sold on plastic discs at grungy stores in strip malls?
And we agreed when video games finally transition to a digital delivery form, and the GameStops all close, then our culture will have lost something. The teen boys will all be in their homes, or their dorm rooms, debating in chat rooms and loosing one of the few public places where gamers can work and congregate. Perhaps one way our colleges could attract the next generation of students is to forgo the fancy new gym, skip the new dining hall, and instead open a GameStop on campus.