As other posters have mentioned, "military surplus" is a complex business.
One of the sources of mil surplus is Defense Reutilization and marketing services
http://www.drms.dla.mil/sales/This is a great place to start looking for items interesting, useful and strange, and you simply bid on it and if you win, you sell it, keep it, whatever.
Another official source is
http://www.govliquidation.com/The selection of stuff is HUGE.