Recently I was tasked with a pretty cool project in which I was to draw up some designs for a music studio mixing room. This was fun because it's quite a different atmosphere than designing say, a typical bedroom. Back when I was in high school I got on this kick where I wanted to design high end custom home theaters, so while not exactly that, this gave me a chance to learn about some of the equipment and the proper way to arrange it in the space. Cool!
There are tons of considerations when laying out a room like this. You've got soundproofing, angled walls so there are no parallel surfaces, bass traps, acoustical ceiling clouds. There are specific angles the speakers need to be set at and specific distances to be seated away from the speakers. It's all really scientific and definitely very cool. Check out this article over at Arqen for an overview of the process.
For a review of the acoustical design course you took in college, check out this one from Residential Acoustics, a very good resource if you're working on a home theater project or any other project with acoustical considerations.