I have been saved by my MacGuyver Bag many times.
In case you didn't know already, MacGuyver was a TV character (I think they may have resurrected the original '80s era show a few years ago). Anyway, this guy was was somehow always able to bail himself out of a bad situation with ingenuity and simple on-hand materials like duct tape, razor blades, clothes pins and coathangers. In the nick of time, MacGuyver could easily build a small thermonuclear device using only some bobby pins, chewing gum and an alarm clock.
If, when I first started playing out, I found a bad cable or a broken connector on my pedalboard at the beginning of a set. I would improvise as best I could. And although I always managed to get away with it, it was a real stress-fest. It only took a few more close calls for me to realize that I'd need as many different spares, extras and adapters as I could fit into a dufflebag, to keep in my car for such emergencies.
Nowadays, after ten years of playing music, I have spares for almost everything I could need in that bag, which I call my McGuyver Bag. Every gigging musician needs one. It not only helps in case of a failure, but is also good for those times when a venue asks you to plug into their weirdly configured mixing board (which is often). As in, mating an XLR female low impedance cable to RTS high impedance male plug to RCA to 1/8-inch Mini female to… You get the idea.
Not long ago, and (as usually happens) right at starting time, I discovered what I thought was a bad microphone cable. It turned out that the mic itself had an internal wire that came unsoldered. I thought it was a deal killer until I remembered that I still had an old headset microphone from when I did a few hayride gigs at a place called River Ranch, near Kissimmee. They needed someone to strum cowboy chords and sing campfire songs through a little battery-powered PA while we rolled through the countryside. I've never liked headsets, but at the time, I figured that on a bumpy hayride, that "Garth Brooks Starter Kit" might keep me from getting my front teeth knocked out by a microphone on a mic stand bouncing around in a flatbed on a rocky trail. After doing those hayrides, I never used it again, but I decided to keep it in the bag, just in case something similar ever came up.
So, when my mic failed, that old headset saved the day for me. It was a good decision to keep that thing. Uncomfortable, but it got me through the gig. And once again, the MacGuyver Bag got it done.