Several years ago, PID was selling something called the 'World View Lamp'. It consisted of a mylar balloon filled with helium with a light source tethered to its bottom. You could reel out the cord from which the light was attached to make a high light or reel it up to make a low light. PID doesn't seem to be offering the lamp anymore, but because of recent events, they probably should. Although, at $800 a pop, you might just want to make your own. What would be needed? A big mylar balloon, string, a light source and some electricity. Or you could make a glow in the dark lightbulb and skip the electricity altogether.
To read more about the original lamp, go to treehugger.