Faster rappelling with a group

Sometimes, a fast moving climbing team can come to a screeching halt when making a rappel (or a few of them.) Somehow the logistics of setting up and completing a rap in safety seems to gobble up the clock like no other part of climbing. Add to this approaching darkness, building storm or the horror of missing happy hour, and reasons to rap quickly become even more pressing. The next time you are stuck in a crowd at a rap station, try this trick:

Feed the rope through the rap anchor as for a normal rap.  Tie a figure 8 on a bight in each strand of the rope, about 1 foot below the point the rope runs through the anchor.  Next, clip a locking biner through each loop and then back to the anchor itself (two lockers are needed for this.)
You now have two fixed single lines, allowing one of two things:  one climber can rap at a time while another is rigging their rope and getting ready to rap the moment the climber ahead of them is on the ground, or two climbers can rap at once on each strand of the rope.  While this is somewhat of an advanced technique, this can really speed up your downward progress. The last climber unties the knots, cleans the biners, and raps normally.

Cautions: 1) Be sure the anchor can absolutely hold the weight of two rapellers at the same time. 2) Watch that one rapeller does not boot rocks down on the other – it might be best if they both depart at the same time. 3) Ensure that all party members are comfortable rapping on a single strand of rope. If the rap rope is free hanging, and/or the rope skinny or wet, climbers may descend faster than they want to.

There are some proven techniques for adding friction to a rappel, read one of them here.