DNA isn't just the building block of all complex life...if you give it about eight hours, DNA can also calculate the square root of 15. It's all explained in this video, which awesomely mixes hardcore science with fairy tale storytelling.
California Institute of Technology researchers Lulu Qian and Erik Winfree recently manipulated 130 strands of DNA into performing a surprisingly complex mathematical operation - namely, figuring out the square root of a number. While this is a breakthrough for DNA computing, the feat itself might not seem that impressive, as it took several hours and quite a bit of finicky fine-tuning for the DNA base pairs to come up with an answer. Even then it only works for at most four-digit binary numbers, or 1 to 15 in our number system.
But the researchers are optimistic that this can be scaled up, and much more complex work can be tried in the future. More importantly, they decided to explain their work with this video, which is a "magic book" all about using DNA base pairs as logic gates. Yes, it's a bit of an odd mash-up (and the background music can be a bit much), but it's one of the coolest explanations of a complex scientific topic I've seen in a while, and it definitely doesn't talk down to its audience.
For a more traditional, but no less involved explanation of Qian and Winfree's work, check out Ars Technica.