Back in my rock climbing days, two friends and I agreed to climb Sam's Swan Song on Cannon cliff in Franconia Notch as a rope of three. Sam's is a fairly long 5.7 route that each us had climbed several times, but one of my friends claimed that it could be climbed in six pitches with a 165 ft rope. To save time, we agreed that each of us would lead two pitches, with the third person self-belaying behind the second until his turn to lead. All of us arrived at Boise Rock separately from different directions, and each of us assumed that the other two would each bring a 165 ft rope.
Of course, you have probably already guessed that none of us brought a 165 ft rope. However, I had a short piece of static rope for towing, perhaps 100 ft in length, in my vehicle, so given that we had all of our other climbing paraphenalia, we used the short static rope to simul-climb Whitney-Gilman, a much shorter 5.7 route, instead. We never did manage to climb Sam's together after that embarrassing snafu.