Apart from standard site suffixes, there's ones such as 'co.(country abbreviation)' i.e. 'co.nl' for Netherlands. I don't find those commonly, though.
.net stands for network..com stands for community.and .gov stands for government.Is it that hard? :/
Google.com will soon make it's move on the government and become Google.gov.
http://www.youtube.com/watch?v=R7yfV6RzE30
.org(asm)