I build in my bedroom. It is also my parents' house. I thoroughly discussed it with them first and foremost. That is simple respect. I spent the last couple months designing, building and testing a spray booth an ventilation system. It was inexpensive, and very worth it. Besides the fact that I don't want to get spray paint all over my parents' house, I also don't want to sleep in a room that smells like paint thinner. The booth I built can handle spray cans with zero smell outside the booth while spraying, and zero smell inside the booth within five minutes
If you are going to paint in your bedroom, I highly suggest a spray booth with good ventilation - and make sure that the fumes, once outside, don't just linger or carry over to a window where your parents might have to smell them and become uncomfortable. Toshi's suggestion for using a plastic storage container is an excellent idea. There are some very inexpensive fans that will do the trick. Make sure they are around 100 CFM minimum - 70 CFM might work for airbrushing, but would probably be too weak for spray cans