There was this stray cat hanging around our house. She would appear whenever we were in the hot tub. After a few nights of her being very friendly (coming up to us), we decided to capture her and take her in. We kept her in the basement bathroom until we got a vet appointment to check her out. The vet did not know she was pregnant.
She started to get bigger... and bigger... Took her to the vet again. She was pregnant!
Like 5 months later, she had six kittens.
More of her story here: http://www.longlivethemonkey.com/brindlekittens/