Before the invention of sails, armadas relied on outmoded ship designs such as the Vikings' 30-man paddleboat and the languorous, elegant war gondola. Sail on a ship as swift as the wind with today's Groupon: for $15, you get a summer sail on the tall ship Windy from Tall Ship Adventures of Chicago (up to a $30 value). Discounted tickets based on age are available, so be sure to check rates.

Honored by former mayor Richard Daley as the flagship of the city of Chicago, Windy spirits up to 150 sightseeing sailors about Lake Michigan on its 148-foot, four-masted back. The schooner's suite of themed cruises, 60–75 minutes long, give customers the opportunity to learn about historical topics such as Great Lakes piracy, Prohibition-era bootlegging, and the Chicago Harbor Lighthouse, all while taking in views of the city skyline or searching the heavens for a sign from your patron astronaut. Interested passengers can help with sail raising and aid the experienced crew with other shipboard activities, learning how to crew masted ships in the process. Today's deal can also be applied toward more costly outings, such as the Wednesday-night fireworks cruises and the 2.5-hour Friday cruises, which help would-be sailors acquire sea legs and fashionable sea hair teeming with plankton and anemones.