Free Roguelike Games

[Eldon]

This guy has a collection of roguelikes he's made, and one is browser based but I can't play for some reason, and one other has a linux version.
http://www.tndwolf.org/

Browser game:
http://www.tndwolf.org/rokr/index.html

Another favorite roguelike is ToME (I use debug mode )
www.te4.org

Another interesting graphical browser roguelike that's not resource intensive:

http://www.unlok.ca/wayward/ (Beta)