Easiest brownie ever, a single serving brownie microwaved in a mug. On SimplyRecipes.com
This will make you to an expert on using the Nikon D90, but this alone won't get great pictures. To get great photos you still need to get yourself to the right place and point the camera in the right direction at the right time, which is a lot harder than mastering the D90. Technically, lighting and the use or disuse of flash is far more important to artistic synthesis than your choice of camera.
This was made using some exposure blending (the same technique mentioned in this gimp tutorial: http://gimpedtutorials.com/index.php/practical-hdr-using-gimp/ ) I'm really starting to like RawTherapee instead of UFRaw for my raw editing. Of course, everything was touched up and combined in Gimp. I'm coming to find that this light painting process creates some really cool vintage looking photos with my trusty rusty D40, a little knowledge on lighting and manual mode, and GImp.