Cool quest from Geas
I've had a character fall victim to a Geas once. My DM at the time was pretty good at tailoring the events of the campaign to fit the PCs' motivations and whatnot. My PC was a CG Cleric of Rudd (Greyhawk game).
My PC's best friend, an NPC, had fallen in battle (saving another PC's life). We rushed the corpse back to Verbobanc in hopes of getting a friendly temple to raise her. No luck. Our only chance was to go to the Cuthbertians, who were downright hostile to the party and had at one point been searching for us to arrest us.
My PC took the NPC into the temple while the rest of the party went on making progress on the main quest. The Cuthbertians questioned the PC at length, and when finally satisfied that the NPC had fallen while fighting evil, were willing to help, but at a high price.
But it was her friend's life. So, yes. The temple raised the NPC from the dead, in exchange for money ... and ... a quest of their choosing to be given to the PC and the now-risen NPC, which they promised wouldn't be completely against the PC's ethos.
The quest was to find and convince the missing Viscount of Verbobanc to return to his post and take up government of the city. It was great, from a storytelling standpoint, because as a CG character this was completely frustrating -- being forced to go track someone down who was doing what he felt was best and try to convince them to give up their personal ideals in favor of the greater good of society? Not exactly chaotic good!
It led to a great session as my PC and the now-raised NPC gathered info, followed leads, and then had a lengthy roleplayed conversation with the guy. She did talk him into returning home, and the geas was satisfied. It was intense, and a lot more complicated than I just made it sound.
So, there's a good use of Geas. How's that?
(Man, did we ever hate the Cuthbertians. We hated them until we died on some random plane in a story we never got to find out the end of ....

)