Practicing climbing can help you burn a lot of calories and become fit over time. Unfortunately, not every one of us have the space for a professional rock climbing trainer. The Blank Slate Training Board could be what you need to practice climbing at home. It mounts in your doorway and lets you add your own unique combination of climbing holds. It has 17 pre-installed standard t-nuts for you to take advantage of.
The Blank Slate lets you attach your iPhone to it as well. It requires 10″ between the top of the door trim to the ceiling, so it may not work in every home. Other than that, it looks quite compact for a rock climbing trainer.