Jacuzzi is the name of the Italian immigrant brothers who first invented a particular type of hot tub. The name has now become synonymous with all hot tubs, much like Hoover for vacuum cleaner. Another example of this is the inventor of safety razors, King Camp Gillette.
And the inspiration behind leotard? Jules Leotard, a French acrobat who invented both the trapeze and the outfit to wear whilst on it.