A few months ago, XKCD posted a challenge to find a plaintext which hashed (using Skein 1024 1024) to a specified value. Inputs were scored based on the hamming distance between the hash of the specified input and the desired hash.
The top scorer, from Carnegie Mellon, found a plaintext whose hash matched all but 384 bits of the desired hash.
I also tried competing in the contest. I used brute force and just hash many sequential values and submitted the best one I could find. I didn't come close at all. As I expected, it was easy to drop the first few bits and get it down to the mid 400s, but each improvement was harder than the one before.
Is there a better way than brute force? When I was competing, I figured that the Skein hash function seemed pretty secure and that I wouldn't be able to find any weakness to speed up the process. Now I'm doubting that the winner could score so well with brute force, even with immense amounts of computing power.