Since the dawn of humanity, man has longed to conquer the ocean, which is why the invention of the boat was followed swiftly by the adoption of the high-five. Celebrate man's triumphs with today's Groupon from SleepAfloat. Choose from the following options:

• For $419, you get three nights on a houseboat for four people in Philadelphia (up to an $889 value, including cleaning and insurance fees).
• For $459, you get three nights on a houseboat for four people in Baltimore (up to a $964 value, including cleaning and insurance fees).
• For $499, you get three nights on a houseboat for four people in Boston (up to a $1,039 value, including cleaning and insurance fees).

SleepAfloat introduces travelers to the waterfront fun of big cities from harbor-side accommodations on a fleet of more than a dozen houseboats. All houseboats set afloat furnished private bedrooms, a spacious living area, and a full kitchen complete with cooking accouterments to whip up on-the-go meals. While in town, visitors might stretch their sea legs by soaking up history at Edgar Allen Poe’s house and Independence Hall in Philadelphia, by touring haunted haunts and pubs at Fell’s Point in Baltimore, or by dramatically recreating the Boston Tea Party by dumping all of their luggage in Boston Harbor. After spending an evening between the stars and gently lapping waves, families can head below for overnight entertainment with complimentary wireless Internet access, extended cable TV, and high-definition portholes.