the great gnomic starbase
This 'ship' circling the local sun on a close orbit is one of the fanciest ideas the gnomes have got lately. A rich gnomeclan liquidated all their assets and spent all cash on used ships on Rock of Bral, Refuge and many other famous shipyards. Instead of equipping every ship with a helm they bought a couple of major ones and transported the ships to this location over a time period of a standard year. Most of the clan remained here and together they have patched a truly unique structure of the few score ships brought here. There are almost as many gravity planes here as there are ships and walking is at best awkward, at worst dangerous.
Why the gnomes gave up their pleasant mountain on Oerth and travelled to this godforsaken place is a complete mystery. And no gnome interviewed ever gives the same reasons, some claim that here they get awesome suntans, others tell about the elmarin-hunting trips, yet another fellow told spoke about how the 24-h days perk up their giant hamsters, etc. The gnomes have indeed taken up many different pursuits after founding the FF, there's indeed a three-ship elmarin hunting company, another fleet boasts with their exploits on every comet that ever comes near (two so far).
No matter that the whole structure is thoroughly gnomish in fashion, all doors are only 4' high and there's no night here, the place is a big hit among spacefarers. They come here from all spheres to meet up with old friends and to gain new, the whole place buzzes with rumors and stories. The gnomes are making a fortune by asking truly ungentlemanly prices for the hotel rooms and meals, but no captain dares to leave his crew to live on the ship and lose his face, he buys the best (and it certainly isn't that good) food for all of them. The reason to all this is an artifact possessed by the gnome chief (an illusionist of 10th level), it projects an aura of general goodwill that has made Flim-Flam such a safe place, it affects most races, neogi seem to be the only immune ones (not that this would be general knowledge, only the chief and a few assistants know of the Ball of Jolliness' existence.)
Lizardmen have lately been asking whether they could lease a wing off the base. They think that this could be a perfect place to let the eggs hatch, the local primary is one of the yellowest stars in the known spheres and the Flim-Flam is a much more stable structure than any of their broodships. The other races have been spouting various displeased comments upon the matter and the gnomes are on the verge to say no to the lizards. Secretly to all the lizardmen have already some ten eggs smuggled here (not a crime, but they want to keep it secret), they are disguised as barristerheads on their luxurious Sznnn'gk dragonship (the ship hasn't moved in 6 months, the eggs are expected to hatch in a few weeks now). What the offspring will be like, is an open question, the lizardmen themselves think that they're going to see the future of the scaly race emerge from the eggs.
Flim-Flam consists of perhaps 100 ships nowadays, its' tonnage exceeds some of the biggest dwarfholds and it has never been attacked seriously, their fleet isn't that big, but the base itself packs many orthodox weapons and some new inventions to surprise the enemies. Flim-Flam has never been moved and no-one expects the gnomes to be able to do so anyway, even though they've installed large Steering Rockets on almost every level surface on the outside. These rockets apparently burn powder, at least a dracon captain, whose ship was 3/4ths vaporized during a test run claims so.
The FlimFlam isn't a nation and there aren't any embassies from the various spacefaring nations. But individuals of many species and even more races brush shoulders constantly in the myriads of shops, taverns and hotels here. Due to the effects of the ball even the most hateful enemies tend to behave themselves here, there's even a Beholderish Racial Issues Committee based here that vainly tries to forge peace between the warring clans. Pale elves (supposedly drow) and mindflayers tend to avoid the place due to the merciless sunlight, but they are indeed occasional visitors here.
Not really suited to specific scenarios, just a Spelljammer variety of the Floating Vagabond or something. Perhaps the PCs could complete a serious night of carousing by going joyriding on the lizard chief's ship.
A criminal with a Brooch of Mind Protection comes over and begins a one-man terror campaign against all inhabitants. The PCs face him at the immense powder vaults, facing a combat against sparks and the Ball's suggestions to "put down yer weapons and head down to Mike's Meadland".
After the PC's foil the criminal's attempts, the gnome chief asks the group to lead 'the hugest ship convoy of all time'. In order to double FF's size, the PCs shall buy tens of ships and helms and lead the fleet here. As a reward they get a 'ship of their own choice', as payment they carry well over three million gold coins to Refuge. Can the PCs keep the cash from thieves, or do they succumb to their own greed.
[Yes, incidentally, I was listening to Black Sabbath (Planet Caravan) and Deep Purple (Space Truckin') when I wrote this one. - V.]