Blink of an Eye, VOY 6
This is some nerd-ass shit.
Voyager gets stuck in synchronous orbit of a planet – becoming its third pole, causing tremors. It is also visible with the naked eye, making it a centerpiece of the emerging civilization on the ground.
Oh – and a second on the ship = a day on the planet. So we watch them go from cave-dwellars to warp capable in less than one week.
A lot of other really great stuff happens here, fulfilling the promise of the flawed TOS episode Wink of an Eye.