Want to make your own AA or AAA battery charger but want to use something more slender than an Altoids tin? This Instructable by Shawn Frayne (sfrayne) is a cool design change for building a charger -- you simply use an old playing card. [Insert magician joke here.]
The project is really basic, using just a few simple materials including "a playing card, some solettes, some magnets and super glue." It doesn't require soldering and takes just about 15 minutes of time.
Here's a video with some details.
Note that this project may get even easier later in the year. The creator, Shawn, writes:
"Where can you get the small bits of solar cells -- the solettes -- needed for these Instructables? Well, it's a pain right now. You can track these puppies down from suppliers in China, but they aren't easy to pin down. So, to make this easier, we're launching a Kickstarter campaign in August to get a solette-packed Solar Pocket Factory DIY kit out into the world. Until then, send me a message or post and I'll try to get you what info I can...!"