One very odd word: Kettlebells
The kettlebell is a cast iron weight, which resembles a basketball with a handle. An ancient Russian exercise device, the kettlebell has long been a favorite in that country for those seeking a special edge in strength and endurance.
Leave it to the Russians... And I don't know if it's really sweeping the nation, but there have been fluff pieces in the news about them that seem to claim as much.
Of course, the fact that one of my favorite boxers, Kostya Tszyu, trains with them is probably influencing my judgement. I'm such a fanboy sometimes.