Extra Vehicular Activity
Also known as EVA, acronym for Extra Vehicular Activity or Space Walk. This is when Astronaut's or Cosmonaut's leave the confines of their Spacecraft to perform tasks in space or on the surface of the Moon.
In March 1965, A.Leonov became the person ever to perform an EVA, The Russians beat the Americans again by just 3 months, when Edward H. White II became the first American to Space walk during the Gemini 4 mission (Ed White later was selected to crew Apollo 1 and was tragically killed during a Plugs-Out test in 1967).
As of February 2001 there had been:
100 EVA's performed by American Astronauts
96 EVA's performed by Russian Cosmonauts
13 EVA's performed by Non-Russian MIR crew
NASA has performed nearly 2000 hours of Space walks in total. A large proportion of these hours were logged during the Apollo Program