For a week at BF's we've been dealing with no functional plumbing. Sewage would leak into the basement. The smell in the house is terrible at first, but not too bad once you got used to it. Sadly, I learned to get used to it fairly quickly.
Last night, the plumber FINALLY managed to get a semi-permanent solution to the old, bent pipe. So no more leaking sewage! He used a long squeegee on a stick and a hose to start the cleaning, and it was DISGUSTING! There were black chunks that had been hiding under the stairs, and he just shoved it all down the main drain in the floor. I sat and watched, fascinated, wondering what exactly each chunk was composed of, but I didn't have the right shoes to go down and get a closer look.
Though I'm still trying to figure out what is the worst. Smell of sewage, smell of ammonia, or smell of bleach all over the house. (No, none of them were ever truly mixed, so don't worry about dangerous gasses killing us.)