when did armagetron first come out?

[<(@_o)>]

when was the first version of armagetron open to the public?

[sinewav]

I assume you are inquiring about Armagetron and not Armagetron Advanced, correct? Check this page out:

http://armagetron.sourceforge.net/old/news.html

Looks like 0.1 was released on 03/29/2000.