Data east Monday night football maybe?

I think a pinball machine is an awesome idea. My only thought of advice would be to let him get settled in first, and get a better feel for his housemates and classes, before adding a pinball machine in.
If classes are going well and his new 24 buddies seem like respectable young men, introduce the pinball machine then.
If after the first two months or so of him being there, he notices that his housemates are pretty rowdy and the parties tend to get a little out of hand, then maybe a pinball machine is best kept away for now. I don't doubt your son will take great care of it, its the 24 other young men that are the unknown. It only takes one foolish act by one immature (possibly intoxicated) young individual to ruin the pinball machine and the fun that comes with it. Also, this might put your son in an awkward spot. If someone I barely knew damaged something a family member paid good money for, I would be tempted to "respond" in some fashion.
With all that being said, I have faith that his roommates will be respectful, and they along with your son would quite enjoy a pinball machine in their house. Let them all settle in and get to know each other, and if everything seems good, bring over a pin for them to play. Before you leave it there though, be sure to set a few really highscores to give them something to chase (besides the ladies haha).