Sandoz:
Okay I refrain from voting again :)

The Atomic and Extinction variants are expained well in the chess variants:

http://brainking.com/en/GameRules?tp=18

http://brainking.com/en/GameRules?tp=28

(IYT has a different version of atomic chess, which I prefer http://www.itsyourturn.com/t_helptopic2020.html )

What about anti-espionage :)