It looks like there was room for a Foosball table there in the back of the garage which makes it look extra cool. If you can paint your garage walls a color that makes it look much better than the bland white as shown below. That garage gym looks fine but if you can invision the walls all being a dark red or blue you will see how much better the garage would look. Painting the walls and giving it some color goes toward making it a unique space and away from being ordinary.
In order to have a really cool garage workout room, you are going to have to give it some character. You need to treat it like any other room in the house and have some paintings or sports pictures or something that will liven up the garage walls in addition to a great paint job. A kick ass gym set will also make it look great along with any other workout equipment you might have. You will need a some sort of rubber garage mat to prevent slipping and to also help identify the space. With a nice rubber garage mat that covers the whole workout area, it will be easy to identify that space as the garage workout gym and that space belongs to you.
Along with any garage gym should be a flat screen LCD TV to watch while you workout. No gym is complete without that flat screen mounted on the garage wall. If you really want to do things right you might also install a stereo system to give you the option of TV or music while you workout.
One reason a garage is a good place for a workout room is because you can open it up anytime and have it air out. In the winter the temperature might be just right but in the summer your garage might get a bit hot. You will want to open or close the doors accordingly to help make it the right temperature. Having a great looking gym in your garage is one of those garage ideas that not everyone thinks about. It will give you a place you can call your own and a great place to hang out.