...when you're playing World of Warcraft.
One of my friends with whom I used to play D&D has been playing WoW for a few months now and has a couple of different characters. When I told him I had bought the game, he made a character on the same server as me so that we could play together.
Trouble is, WHERE you start the game depends on your race. As a night elf, I started out in the top left hand corner of the map. As a human, he was on another continent (note: tonight was actually the first night I realized that the game is TWICE as big as I thought it was when I discovered I could press the "zoom out" button a third time on the map screen... there's a whole other continent I wasn't aware existed).
But tonight, he made the long trek to get to where I was, and we immediately started up some RP ("role playing" for the uninitiated/not nerdy). Next thing we knew, we were sitting with 3 other characters around a campfire, engaging in unbelievable RP... one of the characters told a story with visual aides, there was a debate about the monster races... it was awesome.
Of course, if this sounds ridiculously nerdy to you... it is. But I just think it's cool that this game isn't just good at things like combat and exploration, but it's also the best SOCIAL engine I've ever seen. You can spend as much time and have as much fun interacting with other players without fighting as you can exploring the huge land together and battling monsters.
Best alternative to smoking ever.