So we climbed a route called Guy-Anne, which was a fabulous moderate classic right near Envers des Aiguilles hut. Theoretically we'll do a trip report about that ... one day.
Although the sun was still relatively high in the sky when we were at the top, we wanted to rappel off with a minimum of fuss and a maximum of speed and efficiency. We'd hoped to be able to walk back out to the train station at Montenvers, and head back down to the valley that evening. We didn't quite manage that.
We had the brilliant idea that the person left at the top would lower the rope out to the person rappelling down, in order to avoid the two 60m ropes becoming one massive cluster - something which seems to happen more often than not, particularly if you're in a hurry and don't properly coil the ropes before throwing them. Then, when the half way point was reached, the person at the top would throw the tails over the edge. Fast and no cluster - brilliant, right? This worked perfectly for two abseils.
However on the third abseil, as we definitely should have guessed would happen, the tails of the rope when thrown became tangled behind a massive boulder - this massive boulder being, of course, above Jenzing on rappel. Climbing up (and simultaneously sliding a prussic up for a self-belay), Jenzing worked out what had happened but couldn't actually do much about it as she couldn't climb high enough. The ropes were stuck behind this boulder, in a crack roughly the same width as the rope itself, in a number of interlocking loops and twists, and no amount of coaxing or pulling or pushing would get them out. She couldn't pull too hard or weight the rope in fear of the mess getting even worse (if that was possible), but she wasn't getting anywhere with it either!
Jen made herself "safe" on a handy nearby bolt to keep working on the massive cluster behind the boulder more comfortably, and Mark came down the rappel to try to pull the tails out from above. Slowly, slowly, first one loop came out, and then another and another, until the rest of the ropes were free. This whole debarcle took more than 20 minutes - a long enough time when you're thinking the only other solution is to cut the ropes.
Next time? Lowering the ropes like this was dangerous and stupid - far too much risk that the ropes would get caught and jammed above the abseiler. The lesson has been learned and we'll never do it again!
(On a side note, we completed the rest of the abseils the usual coil-and-throw method. Unluckily, the ropes then proceeded to get caught twice more as we pulled the rope down behind us, with the very end of it getting snagged around something about 20m above the belay. So someone would have to climb up and rescue it. There was now no way in hell we were making that train. It was not our day, really.)