Story 1: Cyberpunk
We stumbled upon a computer chip containing a program which upgrades the AIs of small programs (which are usually Int 6) to something smarter. Two companies wanted it. We were 'in the way' and they were making us offers while sending assassins after us so they could steal it.
Now, the GM wanted us to negotiate with one or the other. We'd get in 'nice' with one, while making an enemy of the other. Something probably connected to a later arc in the campaign.
Seriously? I knew we would be hozed either way. The company would be nice only so long as we proved useful, then geek us when we weren't. That's how the game is played, everyone knows this.
So, I had a copy on my cyberdeck, dropped the chip off in a briefcase on top of a building, and told both parties that the chip was there, though not informing them I told the other company.
The two went nuts on each other trying to get the chip, and it ended with the building getting blown to smithereens. Both companies lost out, both thought the chip and program were destroyed (since it was....)
And we laid very, very, very low... but still had the program.
The campaign was a complete wash... but hey, the players were entertained. Sure, the campaign was over, but it was a damn good adventure for us.
Story 2: Palladium Fantasy
Game Master had a paladin with the PC party, planning an epic campaign where the PCs start as farmers and peons, under the watchful eye of the Paladin Hero, who will guide them, train them, and once they feel comfortable, they make a name for themselves.
The PCs head through some woods with a bunch of peon NPCs and the Paladin. The GM decides to have a 'small goblin raid' on the PCs, to give them their first fight.
Goblin ambushes from tree. Passes Stealth Roll. Gets surprise on the Paladin. Gets a critical hit on the Paladin. Paladin dies.
The PCs freak out. The entire campaign is, of course, a wash. So, the GM hikes up his suspenders, has the NPCs spaz as well, and the goblins attack. The PCs run for the hills, hide out, get together, and try to decide what to do from there...
And the GM lets the campaign run on. Completely different game than what was intended, but hey, you play with the hand you're dealt, right?