The first step to turning your bathroom into a testosterone-filled haven is to whip out a can of paint. Changing the color on the walls is super simple to do, but the result is quite dramatic. When it comes to picking a paint color for your man cave, anything goes. If you want the space to look tough and manly, pick darker colors like cobalt blue or deep red. If you like sports, you can always paint the walls with your favorite team colors.