I bought a Sigma 8mm fisheye lens (and Nikon 10.5 mm) for panorama photography.
It is also a nice tool for other kinds of creative imaging!
(click on any image to see an enlarged version, ca. 1000x600)
        
Horses in Zalk, Holland.
        
Camels in the Sahara, Tunisia.
A hamster's view of the world.
        
Poppies in Zalk, Holland. Note bumblebee in flower.
This big dragonfly didn't mind being approached to within a few centimeters.
So a fisheye lens can even be used for macro photography!
Animals met during a trek in Ladakh, India.
        
Cycle rickshaws in Old Delhi, India.
Boy feeding cow on Durbar Square, Kathmandu (Nepal).
        
Inside the golden temple (Buddhism) at Patan (Nepal).
        
Yaks in Everest National Park, Nepal.
        
Rainbow observed from my attic window.
Application of strong 'local contrast enhancement' reveals the presence of a secondary rainbow.
Autumn leaves.
Children in Lesotho, Africa.
Schoolchildren, Greytown, South Africa.        (Click to enlarge)
Entrance to Neethlingshof wine estate, South Africa.
Pebble beach, Tsitsikamma, South Africa.
Horseman, Lesotho.
Pavilion, Kruger park (bats under the roof).
Schoolchildren, Greytown, South Africa.
        
Souvenir market in Swaziland (left) and in South Africa (right).
Entrance of the Archeological Museum of Athens, Greece.
Temple of Hephaestus, Ancient Agora, Athens, Greece.
Bonis windmill, Mykonos island, Greece.
Click here to open this image at original size (slightly cropped).
Click here to open this image at original size (slightly cropped).