I've been a big fan of HDR photography since the first time I saw some pics of Fenway Park on Flickr that were HDR.
Originally uploaded by richietown
The best way to describe an HDR image is to take 3 to 5 pictures of the same exact photo using 3 to 5 different exposure levels. Then, you use Photoshop (or other photo design software) to enhance the photo and take the best parts of all the photos and combine into one beautiful photo. There are thousands of HDR photos on Flickr and the web of virtually every landscape.
Gizmodo has published a nice little article explaining exactly what HDR is and how to create your own HDR image. This tutorial is simple and walks you through each step using Photoshop CS2 or higher.
As a fly fisherman and outdoor guy, there are millions of opportunities to photgraph amazing vistas, animals, nature scenes, etc - and what better way to capture them than in HDR format. The pictures are even better printed out and displayed - the colors and brightness jump off the page and you will be sure to get several comments/compliments on them.
Here are some cool examples of fishing/Colorado pictures in HDR:
Originally uploaded by ~Luís~
Originally uploaded by iceman9294
Sprague Lake Sunrise in HDR
Originally uploaded by treyerice