For further reading on the Geneva drive... don't miss the spherical Geneva drive design, illustrated in figure 9-3:
Although not Geneva drive related, if you want to combine your passion of horology with human spaceflight, you will truly enjoy "John Glenn's Heuer":
Also, thank you all for the great, related links!
Perhaps you could make a nano (well, micro) scale peristaltic pump out of a really small geneva linkage. Or gears for a little robot that floats in your bloodstream or something like that.