water powered calculator
how about a computer in a whiskey bottle?
how ants find food
for those who like paddles.. how about out of old car tires?
ooh, 15-20 nanosecond exposures of shaped charges exploding
and ok, not so low tech - but:
a kevlar and carbon fiber toy fighter jet.. that can hit 280 mph (450km/h - video)
how about a flatscreen crt?
and ooh! boobies! (yes yes, ok, it's a Digital Image-based Elasto-Tomography (DIET) breast cancer screening system.. but still.. boobies!)