If, like most people, you've had to face the harsh decision of whether to drag your boat or your camper to the nearest KOA, you need to check out the Sealander: a fully functioning caravan that turns into a freaking motorboat.
You Can Rent This Personal Submarine in the Bahamas
It's pretty lightweight and compact, and it can be pulled as easily as a caravan by small sedans.
To exploit its land-based uses, just pitch up like, anywhere, lower the support, and open up the retractable roof. It'll seat six inside, and also features....
... a diverse interior that can be re-configured with a host of add-ons, from a mounted onboard BBQ to an MP3-ready audio package -- and that's not to mention the standard large adjustable bunk.
When you want to use its water-based functionality (or are just bored of it), just roll it backwards into the water.
She's fitted with an outboard motor, meaning you will be anything but.