TFC and Counter-Strike(CS) are two of the most fun multi-player FPSs out there, we play both of them at LAN parties quite a bit. For more TFC/CS stuff, goto the games section.

http://www.planethalflife.com/tfc/ - Great TFC site, mostly just needed for patch downloads.

http://www.planethalflife.com/cs/ - From same site as above, except for Counter-Strike, again excelent.