Last night! I can't cook but I decided I'd make this rice noodle thing (it's like I forget my ability sometimes) anyway, they didn't drain properly, and kept cooking in the strainer and turned into a big pile of glue. Even the kids just looked at it horrified. Thankfully I keep a supply of baked beans on hand for just such an occasion. Waste of $14 of chicken tho...
Well, my worst cooking disaster was when I burnt water, literally. I was heating up a pot with water to prepare my dinner when a friend came over. She was telling me about her latest conquest and we totally lost track of time. When I remembered and ran back to the kitchen, the pot was dried, with black magma-looking marks at the bottoms and a weird smell that until this day I can't really tell whether it was from the pot or the water.
Oh, that's an easy one! I put on a curry to simmer and forgot to turn it down to real low when I went to pick up my kids, got home and hour later and not only had all the liquid dried out, but the chicken had burned so much you couldn't even see it. It was so bad I had to throw out the pot, we had ash in the kitchen and a burnt smell through the whole house for weeks afterward. I learned an important lesson that day - never leave a pot on the stove when you pop out!
I was cooking a pizza but instead of turning the oven on I accidentally put it on grill. I left the kitchen for a few minutes, thinking it was safe to do so, and when I came back I could smell burning and the pizza was already completely black.
I'm lucky enough to have not had any major cooking accidents apart from burning a meal or two. When my wife and I first started dating, she had a cooking accident in our first apartment. She was going to deep fry some French fries in a pot with oil. She set the pot on the burner, and forgot about it. When she took the lid off, the oil started smoking and spitting violently. She tried to bring the pot to the window to get the smoke out but taking it off the burner made it spit more violently, a bunch of oil landed on the carpet, melting it instantly. Luckily none landed on her. The whole incident could have ended way worse than a little bit of burnt carpet.