Wave at the world's deepest hot tub, the AquaCiser. Wave quickly, because that guy looks like he is going down with his monoreme. The manufacturer, Ferno Performance Pools, claims that you can do triathlon training without even leaving the comfort of your own home—if cycling round the utility room is your bag, that is. Never mind the rowlocks, there's also a reversible treadmill on the bottom of the tub, which is 53 inches deep. With 57 jets, five pumps and throttle control valves, the AquaCiser comes in at a cool $17,000. [Ferno Performance Pools via Book of Joe]