National Geographic is reporting the discovery of stone tools in Minnesota that might be 13,000 years old, dating them to the late Ice Age. While they've only been dated by the layer in which they were found at this point, the discovery hints at the continual pushing back of the date at which humans are believed to inhabited North America. If confirmed, the tools would push back known habitation in Minnesota at least 4,000 years.

The Guardian has a really interesting article on prehistoric tools found in the Amazonian jungle. That alone would make for a good find, however, these tools were made and used by chimps, not humans, and point to a "chimpanzee stone age" 4,300 years ago. They suspect that the idea of using stone tools might have even been passed on to both humans and chimps from a common relative even further back, and are hoping to find evidence of older stone tool use in the region.