Luka
MTA:RP Forum Legend
How about skydiving? Where players would book an appointment and pay for the jump for how many hours they have paid. The pilot then flies them via helicopter or plane to the highest point and then they jump. That would be really cool however there is a bug where there's what I call the "ceiling effect" in Grand Theft Auto San Andreas single player where you can only fly so high, if that were removed somehow via scripting then the jump would last longer and feel more "realistic."
Like Majachie said, SEC did that and it was going well, but due to the SEC leaders inactivity it failed. Maybe you can succeed this time!