48-Hour startup challenge

Hi all, My challenge this weekend is to come up with a startup idea and validate it in 48-hours. My idea: A hassle-free way to book kayak rentals online. So many kayak rental companies don't have a presence online, and those that do, have a terrible (if anything at all) booking system. I want to make it super-fast and easy for kayak rental companies to add their products and prices to the site. People wanting to go for a kayak can easily see the nearest rental place near them and book online quickly and easily. I've thrown together a landing page - www.sneakypaddle.com I'd appreciate any thoughts or suggestions you clever folk have. Cheers, Clark