I don't want this to overlap with D&D in any way. Mark's campaign comes first, but here's what I've been thinking about for a Traveller game.
Prologue
Players may recall that in the earlier campaign a lot of the action centered around 2 hyper-intelligent alien beings named Wilbur and Orville (W&O) who challenged the players with calls for "More power!" to feed into an experimental propulsion device. That story line went unresolved for reasons that will be explained here. As time went on W&O actually left to pursue a related line of inquiry. As their contact with the players ended, the previous campaign ended.
Interim
It has been determined from later investigation that W&O's names are not in fact Wilbur and Orville. Those are aliases to hide whatever their earlier identities were, and no leads exist to solve that mystery, but whatever their past was it gave them the ability to rent lab space in a research station around a young star, Hept Klez B. Only about 800,000 years old, Hept Klez was expected to have a life of at least 4 billion years. Because its planetary system wasn't finished forming there was no evolved life on any of its orbiting bodies. The scientific station on Hept Klez 9, home to about 75 researchers was the entire population of the solar system.
Then the star very mysteriously exploded with no explanation. A star of that size was supposed to form a red giant at the end of its life, but it blew like a supernova. The scientific station was destroyed and everyone living there was presumed dead, but questions remained.
Present Day
That was 38 years before the current campaign begins. 2 hyper-intelligent beings now calling themselves "Wilbor" and "Urville" have mysteriously reappeared, as though they haven't aged a day, and they are trying to recruit assistance with a new research project. The previous official records for Wilbur and Orville are still open and science officers from the Galactic Fleet would like to interrogate them if it could be determined that these 2 new characters are the same beings.
So that will be the situation players will engage in - W&O launching an expedition while authorities are spying on them and the players with them to figure out what might be going on.
So far the only details W&O have revealed are that they want to find a large special complex carbon-silicon matrix crystal because they believe it will help them to understand an object they keep in an ultra-strong magnetic containment field. The object is roughly the size of a USB drive but when you look into one end it seems like a window into the heart of an exploding star, and without containment it sometimes vents dangerous amounts of energy.
Game Details
I haven't been able to find my original Traveller set but there's a current core rulebook published by Mongoose Publications. I got one from a place called Sci-Fi-City in Memphis TN for $55. I'll make copies of the character generation process to bring along to D&D session in case anyone wants one. I'm not sure what kind of interest there might be in hanging around with a couple of insane space pigs, but we'll see how it goes.
Note that Jon has gotten ahold of the rule book in PDF form (about 34MB in size) and he's got that posted in the Documents section of this web site. I've printed out tables that make character creation easier so please let me know if/when you want to get a character started.