Interactive Leonardo project, just released by the Spanish National Library. I've just heard of it thanks to my friend Paco Oca. Don't worry about the homepage being in Spanish. Click on the big picture on it and start navigating.
When you get to the virtual reader, you will notice that, besides enjoying the art in Leonardo's two Madrid Codices, you also have access to extra features, such as 3D animations and translations of some of the notes scribbled around the drawings. You can also zoom in to see the illustrations with more detail, share whatever pages you wish on Facebook and Twitter, and print them. The whole thing is pretty impressive.
I have included a small random selection of screen captures right underneath this paragraph.