Zorbing is the activity of getting inside a huge see-through plastic ball and rolling down a grassy hill in it. The ball is really two balls, one inside the other, with air between them, so the person bounces about in the middle instead of being hurt. Sometimes there is water inside and you slide around like clothes in a washing machine; sometimes you are strapped in and turn over and over with the ball. It is a holiday-and-theme-park thrill, not a sport with rules or teams — people do it once, scream, take a photo, and talk about it afterwards. It began in New Zealand in the 1990s, and Zorb was originally a company's brand name. The little b became a common word the way people say 'google' for searching — so you will see it written with a small letter, and the makers do not love that. You mostly meet it as the -ing noun: 'go zorbing', 'zorbing is popular here'. The verb 'zorb' exists ('we zorbed down the hill') but sounds playful and is much rarer. The word is informal, cheerful, and slightly dated — it was everywhere around 2005 and is quieter now.

太空球 / 悠遊球（滾大球從山坡滾下來的那個活動）