Of course if this isn't to your liking, there are tons of other things you can do instead. Depending on the size of the cellar you could bring in your own sauna equipment or install a portable infrared sauna. With a home sauna and perhaps some other additions, you could have your very own gym.

The cellar is the perfect place for something like this because it is out of the way and very private. You won't need to worry about people being able to see you through the windows, and you can have the workout room you've always dreamed of without needing to sacrifice any of the rooms already in use inside the house.

Some cellars are quite large, and if you are fortunate enough to have a sizeable one, you could turn it into something like a studio apartment. If you built in a couple of extra walls, and if it was equipped for plumbing, you could install the necessary bathroom fixtures and kitchen fixtures to make a nice little guest apartment.

Even if you are unable to add in the plumbing and fixtures, you could still make an exceptional bedroom out of it, and have a perfect private guest bedroom. If you aren't the type to have many guests over, then this might not be right for you. Another good idea is to make it into a study. You could do all of your work in comfortable silence, without all of the distractions of a noisy household.

If this doesn't suit you either, then why not make the cellar into your own personal relaxation room? You could install spa accessories such as a hot tub. There is a lot less to maintenance for an indoor hot tub than for a regular outdoor one, so this is actually double the awesome. You could have the hot tub, big bean bag chairs, a bookcase full of your favorite books, and whatever else makes you feel most comfortable.

A media center is always great to have, but many people just don't have the room to install something like that. If you made your cellar into your media center, you wouldn't have any such problem! You could have a big screen television with surround sound and a huge stereo and your computer and your giant shelf full of every single DVD ever, all in one place.

One last idea is to turn your cellar into a library. You could have wall sized bookshelves filled with all kinds of different books—you could sit and read all day long with no worries of being disturbed.