There is YouTube video with 23 sledgehammer exercises, several ones already mentioned are on there. (fireman, chop wood, flip the lever...) 
But there are also many more advanced moves if you are feeling adventurous. 
Just thought I share it with you guys.
 http://www.youtube.com/watch?v=-MYjTG4130g 
			
			
									
									
						Full Sledgehammer Workout
Yeah, this is the guy who had to be reminded to give me credit for the idea -- which, to his credit, he promptly did.
http://everydaysystems.com/bb/viewtopic.php?t=1871
Does seem to have worked rather well for him! Plus some of the extra moves are interesting.
Reinhard
			
			
									
									
						http://everydaysystems.com/bb/viewtopic.php?t=1871
Does seem to have worked rather well for him! Plus some of the extra moves are interesting.
Reinhard