Something to do in your spare time is to practice free association. It doesn't matter if you're on a road trip, or drunk, or just plain bored...
Players: 1 - infinity
How to play: One person starts with a word or phrase. The next person says the first thing that comes to mind that reminds them of that original word or phrase.. and so it goes around the friends. The kicker is that you can't repeat what someone else has said, unless of course it's the first word, in which case you've "won" the game. It's hard to tell if you've really won though because what if your saying that word was intentional and not simply free association?