I want to start a space colony RP.  I have two ideas:
1) The first colony was a century ago.  Many asteroids were mined for their resources, some of which were inhabited just long enough to grab the materials that were worth mining and selling.  I bought one of the asteroids and decide to recruit folks from around the solar system to help me build a trade/mining/tourist city there.  An economy will already be established in the area, with prices in terms of gold grams or Mars Gold Credits (MGC), a digital currency with one credit equal to one gram of pure gold.  Commodity prices will be in Equal Mass of Gold (EMG).  For example, P-239, at 10EMG is worth ten times it's mass in gold.
The asteroid we are on is a silicate asteroid that was abandoned 20 years ago when prices crashed and the mining technology couldn't keep up cost-wise.  It has a few basics on it that were left in place, such as airlocks, atmosphere generators, backup reactors, etc, that weren't worth taking with them or they decided not to take.
2) First Martian colony.  Support from Earth is 6 months away, so if we screw up we are all likely dead before they get there.