From QWiki

A grenade launcher rocket jump (GLRJ) is a flashy use of explosives usually reserved for showmanship but with a couple rare practical uses. It is based on the RJ. A grenade is set to explode, and at the moment before (not after!) it explodes, a RJ must first be executed. The perfect GLRJ will be equivalent to a RJ that fired two rockets at the same time, and therefore will be twice as far.

The crucial part of this trick is, of course, to time the explosion of the grenade. The easiest way to do this is to stand still on even ground, and fire a grenade straight up into the air. Because every grenade is fired with the same force, it turns out that every grenade will explode right after its second bounce off the floor, when fired straight up. So: shoot a grenade up, wait for it to hit the floor a second time, and RJ at that instant!

Once the player gets a feel for how long it takes for a grenade to explode (3 seconds), he can time it less conspiquously just by throwing it on the floor horizontally, or in other ways (such as sticking it into a slope).

One practical use of GLRJ is on DM3: it can be used to get from the pent spawn point to the window above (although a single rocket jump from megahealth (or lifts) can also be used and it is cheaper (and easier)). The fastest route on DM6 from GA to RA, traditionally a measure of RJ top speed, is done quickest with a GLRJ start, and as many RJs off the walls as possible (the fastest time so far is 2.0 seconds by BogoJoker)

QuakeWorld terminology
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GA | YA | RA | Mega
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Binds | Bunnyhop | CFG | Demo | Duel | FFA | Frag | Rocket Jump | GLRJ | rpickup | pickup
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