As others have mentioned, there is an indoor and outdoor option. (Indoor is way better in my opinion, outside you are subject to the sun's glare or chill of the wind) Tickets are purchased for $18 at the gift shop (if you stay at the Venetian, they give you a voucher for 50% off when you purchase a full price ride).
Domangio (can't remember his name exactly), our gondola driver, was amazing. He was super friendly and lots of fun. The ride itself lasted roughly 10 minutes and he sang two songs and chatted with us the whole time. It was a fun experience if you happen to be looking for something different!