From Quake Wiki
Telejano is a modified Quake engine. It is derived from the TomazQuake engine, but Telejano is bigger, badder, and better. Telejano adds in so many new features that it is over 1.5 megabytes in size: More than twice the size of the original TomazQuake. It is not as detailed and complex as Tenebrae, but both engines are completely different and we think you should try Telejano.
The most important goal for Telejano is to enhance Quake, Scourge of Armagon?, Dissolution of Eternity?, User-Made Maps?, and User-Made Mods?, without having to recompile/remake them. Many dull and simple graphics and effects have been replaced with newer effects. Such examples include: lighting effects, explosion effects, fire particles, sparks come out when a bullet hits the wall, you can see lighting caustics under the water, you can see steam coming out from the boiling lava, launched rockets, grenades, and lava balls leave smoke trails behind them, blood looks alot more realistic, fire bursts out of the lava, httpcustom surface fog, model repeating and fading away (for grass, trees, clouds, etc.), rain effects, snow effects, dungeon lighting effects.
Another major feature of Telejano is the ability to replace textures, models, and skyboxes. Here you can download hi-resolution textures, hi-resolution md2 & md3 models, and hi-resolution skyboxes. httpLocalMenus can make setting up all of this eyecandy easy.