SpaceEngine let's you zoom through _galaxies_ like that old windows screensaver was for stars. I've always sorta understood that the universe was "big", but it never clicked how infinite it really is until I zipped through SpaceEngine for an hour.

That said, Elite: Dangerous is pretty awesome. It helps ground how far away everything is. Even with the game's FTL travel, the fact that it takes actual weeks to reach Sagattarius A* boggles the mind.