I've got a new MSH game started on my yahoo group Multi_Verse. Player characters are scions of the Norse Gods. The campaign will take you through Ragnarok, with the scions moving from hero to demigod to god.
This takes me back, wish I had the time to get back into some serious tabletop!
Back in the day I dabbled with the following..
AD&D Marvel Heroes WWF Doctor Who Star Trek TMNT Blue Planet Paranoia Sla Industries and a few others that I just can't remember the names of.
But I really enjoyed playing a couple of games:
A real X-files kind of a game. I started running this with a handful of players, I bastardized the setting and had them in a bunker in the middle of the US. They were in the only "time neutral" zone in the world. The rest of the planet had been to some degree or other corrupted in terms of its time-line. The players were mankind's last hope of resetting the time-line and putting right all that had gone wrong.
Shamelessly it drew on such classics as X-Files, Terminator and Quantum Leap.
This was maybe my favourite ever, again I was the GM. The highlight for me was when after a few years of play the characters found themselves transported forward in time, to the modern the day. Watching them investigate their own legend back in the wild west. Putting together the clues of what had happened to them back in the late 1800's from old reports and the like was a classic. Also, one of the players decided to quit the game, but not before he agreed (unknown to the others) to be revealed as the traitor. Special stuff seeing the players faces when several years of trust was utterly broken in a most violent manner!
Oh, and I forget about Shatterzone!
Another game I GM'd. This detailed the collapse of the outer ring of the galaxy, The Shatterzone. A ring of debris and dying worlds that kept our galaxy separate from invaders. When that started to crumble and an ancient prophecy foretold of the heroic deeds and ultimate death of one of the players. The game became a slow journey to that inevitable moment. To save a galaxy or save oneself. RP is always best when the scale is right and the emotional involvement of the players is garnered.