Meet the ALFI FireHotTub: an awesome portable outdoor hot tub that burns wood to heat water. Just fill the tub with cold water from your garden hose, light a fire in the pit, and you are set. The hot tub can hold 200 gallons of water. The water passes through the metal coils and stays warm. You also get a stainless steel windscreen panel that attaches to the chrome pipes and keep you safe from fire flames. As you can see in the above GIF, you can take this hot tub with you in the back of your truck. Not cheap but looks quite fun to relax in.