Last long bus roadtrip I was on, 4 of us got a multi-hour card game going. We played Hearts for money to keep it exciting. If you have not done it, you keep a 5th column with the scoring average. At the end of the game, people below the average pay in per point, those above the average win. You can play small stakes (penny a point) or higher stakes. Shooting the moon is more nerve-wracking when money is at stake.
Believe it or not, it really did make the time go by faster. If no one has palying cards, buy them at the next truck stop.