Christmas special: 2 Rock-Its for $15

You might have seen the Rock-It on TV's "Shark Tank" or some other show. It's a clever gadget that turns almost anything into a speaker. Connect one cable it to a mobile phone, iPod, or some other music device, then attach another to a flat surface and you instantly get a loud boomy speaker.

The Rock-It works with any flat surface, like a window to desktop, but it works best with a hollow object like a cardboard box or a plastic beer cup.

Orig Audio sells the devices for $19.99 on the company's website. But this weekend you can get two for $15 with free shipping if you use the promo code "1515" at checkout. The offer expires at 12 noon EST on Monday.

Oh, there's one catch. The two Rock-Its are red and green. You know, for Christmas.