The Great Role-Playing Crossover

We've all done it. Left a campaign in the swing of things, plots and subplots unresolved. It happens. Friends move away, time - that dreaded enemy - gets the better of you, interests wane.

Sometimes you'd like to get back to that story, you know, just for one last game. End it properly. Have the characters go out in a blaze of glory or live happily ever after. And if you're like me, you'd like to resolve all those campaigns SIMULTANEOUSLY.

In my multi-genre GURPS campaign, I left players wondering why the hell the universe was changing around them. Were the Atlanteans really responsible? Did their parents know what was going on?

In my DCHeroes campaign, one hero fell into the microverse with no hope of escape since his teammates will now likely never shrink down to find him.

In my Planescape campaign, will our erstwhile band of berks ever find their way to that mythical demi-plane?

Or will they be like all the others... trapped in the limbo of our own indolence?

MY CRAZY IDEA: Invite all present and past players for a huge Crisis on Infinite Earths event in which all those campaign worlds come together. As the original Crisis comics had it: Some will live, some will die, but the multiverse will never be the same. Players will cycle between their various character sheets, the mage teaming up with the Warehouse 23 agent and the superhero to stop the entire multiverse from ending, and in the process they will all find closure.
Looking at my various campaigns (those above and others), none of them really discount the existence of a multiverse. Lots of preparation just to get the various characters or worlds converted into the other systems, but it's a big one-shot event, so it's worth it. (Sure, it would be easier to convert everything to a single common system, but much more fun to skip between systems as you skip between characters and universes.)

I thought it might happen this year with two old players coming back to town, but one of them just got his sorry ass pregnant and has to move back in with his wife. Booo.

Still. The dream lives on. It's just a little more complicated than before. And in another dimension somewhere, that game is being played, and all our characters are getting their dues.