Charging the Asus Transformer (Prime)

Can you charge the Asus Transformer (or the newer Prime) without the keyboard dock? Since the tablet itself does not have any USB ports, I don't see how you could charge the tablet without the dock or a very clunky proprietary charging cable. However, It seems insane to manufacture and market a high-end tablet that can't charge without a giant peripheral (and sell/price the thing independently too). Am I missing something? Or, is Asus just insane?