Sailing around the world is much easier when you learn which knots are edible and why dolphins aren't marriage material. Learn the basics with today's Groupon: for $40, you get two tickets to the History Sail or Tropical Sail from American Sailing Tours (an $80 value).

American Sailing Tours, featured on Wheretraveler.com, loads citizens onto the good ship Summer Wind for relaxation and education on the Delaware River. The jolly crew handles all the hatch-battening, jib-cutting, and barnacle frying on each excursion. Meanwhile seafarers learn about the Delaware's contributions to Philadelphia history on the History Sail, which embarks once per day, six mornings a week. Customers on the Tropical Sail tap sea-toes to the beat of beach music from the Caribbean, New Orleans, and New Margaritaville two or three times a day depending on the time of year; check the online schedule for an idea of departure dates and times.

Visitors will find the large, white sails of the Summer Wind billowing above Pier 24 at the Philadelphia Marine Center. Thanks to its masterful design by noted naval architect Thomas E. Colvin and the help of magic, the steel-hulled ship bobs above the water's surface as customers can take in the Delaware's views from the ship's 20 padded cabin-top seats.