Build a fold-down workbench that eats up zero floor space when not in use. We used a 30-in. solid-core door, but you can use other materials such as two layers of 3/4-in. plywood glued together. From the Family Handyman
Folding Wall-Mounted Workbench by Bench Solution saves valuable floor space, provides a heavy-duty work surface with a 400-pound load rating, folds down to take up less than 4 inches of garage space, and can be customized for your height. (Vehicle might still have to be parked outside while the project is in process). Posted by Chad Gookin 2012-10-23).
This fold-down worktable is perfect for the craft or DIY enthusiast who doesn't have a lot of space, such as in a spare bedroom, shed, or garage. When not needed, the worktable folds down flat against the wall.