TARDIGRADES (also known as Water Bears or Moss Piglets)
The king of the extremophiles! Extremophiles are organisms that can withstand amazing extremes, of temperature, pressure, radiation, whatever. But none of them are in the class of the tardigrade! It can cope with near-absolute zero, 300 degrees Fahrenheit, pressure SIX times greater than that found at the deepest depth of the Earth's ocean and radiation levels a thousand times higher than what would kill an elephant.
In 2007, NASA sent some tardigrades into outer space. They were left outside the space shuttle for TEN days, exposed to hard vacuum and intense levels of UV radiation and then brought back to Earth. They were fine!!
There is a lot of stuff about them on Youtube - this is one link but have a look at others. The Wikipedia entry is also very good and has links to more stuff.