Sailing. But I do it much cheaper than I might otherwise. (Definition of a boat: A hole in the water into which you pour money.) I sail at a relatively low cost club. Unlimited sails Apr-Oct for $249. No boat maintanence. Serve on the Board as President actually. Which itself is an expensive hobby, because I then need to serve as a leader making donations.
Skiing. Learned to ski/race when I lived in Alaska. We had season passes then (parents needed something for us to not all go crazy in the winter and put this budget towards skiing). Now, it's so expensive I only go 1-2 times a year. Don't get much so much use out of my equipment.
Traveling. Love to travel to foreign countries. Been to: Canada, France, Italy, Monoco, India, Switzerland, Mexico, Hong Kong, Cambodia, Thailand, Vietnam, England, St. Martin, Domenica, Grenada, Tobago, Barbados. ETA: Bahamas. Upcoming trip in October: Aruba, Columbia, Panama, Costa Rica, Grand Cayman. Likely trip next spring: Brazil.