Know why I love living in California? The. Beach. However! There aren't many plugs out there. That's where the Eton Soulra XL iPhone/iPod speaker dock can come in.
Big brother to Eton's Soulra Solar Powered Sound System from last year, the XL version uses a retractable 72 square-inch enhanced monocrystal solar panel to charge its 2000 mAh lithium ion battery. It's got eight speakers and should last for 5 hours of continuous play.