Imagine being able to play a friendly game of bridge, hearts, scrabble, mah jong, chess, Doom, HalfLife, Gran Turismo or just about anything else with your fellow passengers. Maybe blackjack or poker -- for real money -- is more your thing.
It shouldn't be too difficult (or expensive) to create
software and hardware for an existing portable gaming device like a Nintendo GameBoy that would connect wirelessly to an onboard server.
You'd then have the ability to choose from a generous library of activities. Single-player games similar to those Flash games you find everywhere on the 'Net, maybe a few classic arcade games, maybe a few 'new releases'; multi-player games that range from popular favorites like Scrabble or Hearts to arcade-like first-person shooters, driving/racing games or aerial combat games; or maybe just chat with other passengers, send email, or surf the web (additional charge for 'Net access, probably.) Other online passengers would be identified by their seat number, so you could actually go meet the other gamers if you wanted to.
Once the captain turns off the "fasten seat belts" sign, flight attendants would start passing these little units out. I'm thinking most airlines would assess a small rental charge. The real money, however, would be from inflight gambling. You can play single-player games like slots or video poker, or you could sit down at a virtual blackjack table with your fellow inflight gamblers.
There are probably laws that govern gambling aboard flights over land, but wouldn't it be ok if you're flying over international waters? Those are the really long flights where a distraction like this would be most welcome anyway.