On a serious note, I never go anywhere without a pocket knife. (Well, that is expect for commercial flights, and even then, there is one in my checked luggage.) I can think of at least three times while cycling when a pocket knife came in handy. 1. Riding partner went down and had major road rash on his right thigh and his shorts were in shreds. We were able to take his jersey and strap it to his injured hip by cutting and splitting about half a length of bar tape off one side of his handle bars and tying him back together as it were. 2. Rider was wearing shoes with laces that got so badly tangled in her drive train that it seemed almost impossible to get them out. Was able to carefully cut away portions of the shoe lace and still have enough for her to keep her shoe relatively snug for the ride home. 3. I needed to cut a larger boot patch for a sidewall rip in my rear tire than the one I carry in my seat bag. I was more than willing to cut a section of the insoles in my shoe to do the job. The insole was easily replaced later.