I love the idea of anything that is human powered. The K-TOR Power Box allows you to charge your gadgets (under 20W) using pedal power. The K-TOR Power Box has a standard two prong AC outlet which should have no problem charging tablets, smartphones, portable game systems, low-power netbooks, etc,
A couple of use scenarios come to mind. Use it under your desk while at work to burn extra calories while charging your smartphone. Or, even better, have your kids only charge their portable game systems via the Power Box. See how much they like playing games if they have to provide the power.
The Power Box weighs just 4 lbs and folds into a cube shape when not in use making it perfectly portable.