[jloughry]

Lightsail. You carry a laser and a lightsail. You shoot the laser at the black hole and the laser light gravitationally slingshots around the black hole, returning to you with more energy than you gave the laser. The returning laser light pushes your lightsail. The black hole needs to be moving for this to work, although it doesn't really matter what direction the black hole is moving.

[lutorm]

It does very much matter which direction the black hole is moving; it needs to be moving toward you or you won't get any blueshifting effect, which is the entire reason the energy budget works out.