In a game I was playing in a few years ago, the campaign was pretty much centered around collecting up these map pieces to find some ultimate nullifier sort of device to use on some apocalypse doom kobold...anyhow...I had to roll up a new character just as the main party was coming up with zero clue as where to go next. She wanted to get to a particular city way off track so she could murder a relative, so she suggests, 'You know...we could probably get all the info we need in this city over here. I happen to have a map.' Honestly, that really was probably the best shot we had since no one had any clue.
Couple months later, game-time, we arrive at the city to find it's been sealed off by a giant prismatic sphere. The other fighter decides to activate his winged boots and fly to the top to see if there's a tiny hole up there. He doesn't find a hole, so he decides he'll just try to plow through the wall. Somehow, he manages to make his saves until he turns to stone and then gets shunted off to the Nine Hells, unbenownst to the rest of the party.
Somehow, possibly through metagaming, we figure out where he went and suddenly everyone's pumped to pop over to the Hells and get him back. After a month or so of tromping around the circles and another month just farting around the planes, someone finally decided to wonder how we got so far off track and they realized my character was the start of it all. I told them, 'I just wanted to go to the city and everybody agreed.'