CNC Panel Joinery from Make:
Here's a really useful article on CNC panel joinery methods by Make:..
Most of the images show laser-cut pieces, but could definitely be adapted for use on a CNC router or machine. In some of the images, you'll notice there are sharp corners that would not be possible using a CNC machine. With a CNC machine, you would need to create overcuts to account for the thickness of the end mill. If you're having trouble figuring out how to fasten parts together in your designs, this article is definitely worth a look. Find the article here