Duct tape... gaffer tape... electrical tape... thank goodness we live in a world where strong, relatively waterproof adhesive tapes can be purchased at any hardware store for a modest amount.

I wrap a few feet of duct tape around a plastic film canister or soap dispenser for my tours. I've never needed more than a few inches, but I have always been glad to have tape. I once fixed a broken rear rack -- one of the welds snapped -- with dental floss, crazy glue and about four inches of duct tape.

I read in book about emergency mountain bike repairs that a cracked frame can be made (somewhat) ridable by bracing the tube with sticks, and wrapping the area with duct tape. The author does not explain how it is possible to smash up a frame so badly...