Photo of the Entire Night Sky. By Two Guys.
This is incredibly awesome! Nick Risinger and his retired father traipse around the US and South Africa with expensive cameras taking an entire visible-spectrum image of the night sky.
The final product is a 5 Gigapixel mosaic from 37344 images, assembled with free software on a GNU/Linux laptop. To jump straght to the goods, visit the interactive flash-based viewer (a google-maps sort of interface) to browse the thing. Awesome!
A creative-commons "Attribution Non-Commercial" licensed download of a 4.5 megapixel image is also available and also large prints.