This is so cool!
http://blog.wired.com/wiredscience/2008/10/cell-illuminato.html "Tsien, along with co-recipients Osamu Shimomura of the Woods Hole Marine Biological Laboratory and Columbia University's Martin Chalfie, works with green fluorescence protein, or GFP. In nature, it makes crystal jellyfish glow. In a laboratory, spliced into a genome, it lights up whenever a target gene is activated.
This allows researchers to observe cellular function at a level that was previously impossible. (Think of it as the difference between having the pieces of a mechanical clock and seeing the clock run.) It's a rare paper on gene or cell function that doesn't involve GFP -- if not directly, then in the research that led to it.
And that's why basic research, so often criticized for being pointless and esoteric, is so important."