For our group's 20th Year Anniversary Game we ran a round-robin, where everybody took ALL of their characters (each player had between 4 and 9), divided them into seven teams, and were simultaneously sent to seven different times and places to retrieve the individual pieces of the Rod of the Seven Parts, each scenario having a different DM.
I had around 20 Battletech/Sci-Fi figures that had been part of large miniatures lots bought on EBay so put together a sci-fi game for my piece. They were on a huge space station that had once been a prison, the male prisoners had revolted and taken charge a half-century earlier. Their mission was to get the rod piece, held by one of the prisoner gang factions. To add to it, a Ming-the-Merciless type with a female assistant had recently boarded, so there was a risk that a new generation of prisoners could have been born. The party's secondary mission was to rescue her, or if necessary, kill her.
The game went well. Yes, they found space armor and laser rifles, which I let them bring back to their own world at the end but I made sure that each has a limited number of charges and cannot be recharged. They also brought back the female assistant, who I expected somebody would pick up as a PC given her unique background, but nobody has yet.