I must admit to having a wife like no other.
I once was rebuilding a Honda CB550 four that had been sitting in a shed for years; after the obligatory carb cleaning, plug swap, disc brake overhaul, oil change and new battery, the time had come to fire it up and test ride it.
I filled it with 2-1/2 gallons of gas from a topped-off gas can, then started cranking. It fired up soon enough and started coughing, sputtering and backfiring. I hadn't yet installed the main breather hose or the airbox, and didn't notice it was pukking oil out the top and drenching the backside of the engine; I also hadn't put clamps on the fuel lines, which were a bit brittle and dribbling at both ends of both hoses.
Happily revving the engine, I yelled at Sally: "let's go for a ride!", to which she hiked up her blue-jean skirt and jumped on the back. As I kicked back the sidestand, (engine still backfiring quite a bit) I could feel my leg getting warm and I looked down and noticed a flame licking up from under the gas tank!
I yelled at Sally to get off the bike and as soon as she cleared off, I jumped off and the bike fell on it's side, the impact causing the fuel lines to pop off the petcock as the pressure built up from the sloshing. Next thing you know, flames were covering the entire engine area, with two "torches" of fire shooting out of the petcock. Obviously, a backfire had ignited the oil on the backside of the engine.
While I was figuring out a plan of action, Sally stripped off her skirt (thankfully, she did have on a slip underneath) and started trying to smother the flames! Although it wasn't very effective, it brought a tear to my eye while I ran for the fire extinguisher in my truck. Sally was still waving her skirt (now burning) around, with very little result, as I popped the pin on the extinguisher and it wimpishly spat out ONE little cloud of white powder, and gave up. Sally ran for the garden hose and came struggling back with it stopping and starting as it uncoiled, kinked, uncoiled and kinked, finally straightening out and providing a nominal stream of water which served perfectly to spread the fire to the entire bike and surrounding area. By this time the flames were 6 feet tall.
My Dad had heard the commotion, came outside and saw our frantic situation, then set about to find his fire extinguisher; I, in the meantime, was running for the house to get the kitchen fire extinguisher (everyone has one next to the stove, no?). I returned ahead of my Dad, and proceeeded to pop the safety on my 2nd extinguisher, then gave it all it had with a measley 5 or 6 second blast which somewhat started to put down the flames (by this time the gas in the tank as nearly spent, the tank itself swelled and butterflied to nearly twice it's original proportions).
With the flames still out of control, my Dad arrived on the scene with his industrial-sized extinguisher and proceeded to put out the fire once and for all. He sheepishly averted his eyes as Sally pulled her singed, smoldering skirt back on. She gave me "the look" and said "you'd better be glad I was here, or this would be worse. you owe me a new skirt".
To this day, I wonder if my Dad purposfully waited (maybe at my mother's insistence) till the bike was pretty much toast, before putting out the fire.
I did end getting the bike sorted and running again later, and got some use out of it with a crispy seat and rear tire with one quarter section toasted.