DeFRaG is a modification of Quake III designed for doing timed runs in vanilla quake 3 and cpma physics along side trick jumping and even team trick jumping in over 15,000 community made maps. Similar to what speed runners do on a daily basis, but alot more hardcore. The original idea and the name defrag came from a user named Belzel and most of the programming was done by Cyril "cgg" Gantin, you can read more in the wikipedia page. You can also join the community Discord server at the official link Discord.me/DeFRaG and Official Steam Group. DeFRaG's home is q3df.org and there is usually a yearly cup called DFWC(defrag world cup). 2017's prize pool was over 5,000 usd! Even the mappers got money!
First download quake 3 and DeFRag. Then I would recommend using iDFe.exe instead of the default .exe's, place that in the same folder with the others. You can then either use /connect ip.address in console and automatically play online and download maps or download maps to play here. The server list linked above(connect ip.address) has its own set of commands here. DeFRaG also allows custom content and skins which can be found here and also in the mods section of this site.
Better Default Settings
By default the game is not quiet setup right, I'd recommend setting the following settings in console or make an autoexec.cfg in the defrag folder and copy/paste these into it.
bind MOUSE2 "+moveup" //jumping with right click is a significant improvement over spacebar
seta cg_fov "115"
seta com_hunkMegs "512"
seta com_introplayed "1"
seta com_maxfps "125"
seta com_maxfpsMinimized "30"
seta com_maxfpsUnfocused "30"
seta com_zoneMegs "16"
seta dl_source "http://ws.q3df.org/maps/download/%m"
seta cl_allowDownload "0"
seta cl_mapAutoDownload "1"
seta cl_maxpackets “125”
seta snaps “125”
seta rate “25000”
seta cl_packetdup “2”
seta r_texturemode "gl_linear_mipmap_linear"
seta r_mode "-2"
Learning how to DeFRaG
There is a perfect video to get you started, Genesis - The Beginning Of.
The map used in the video is tr1ckhouse-beta3