prboom is a version of Doom using the Simple Direct Media layer (SDL) library, which enables it to use XFree86, OpenGL, Linux framebuffer console, GGI, SVGALib or even color or monochrome text consoles as display. There is an additional OpenGL renderer as well, which has been disabled for now.
prboom is based on MBF and lxdoom, which in turn is based on Boom, a freely available port of Doom for DOS, written by TeamTNT (http://www.teamtnt.com/).
To play you need some maps, called "WAD", a free version of Doom is included in the Games/freedoom package. You can use any other Doom WADs as well.