Most hacking challenges suck. The most recent one (The Zero[-clue] Challenge) seems to revel in its suckitude. A) They make it seem like it's just a /dev/zero'd drive, B) in actuality it had gnupg symmetric key encryption between the physical drive and the ntfs layer so in addition to recovering the data you have to hack gnupg symmetric, while C) doing this without physically cracking the drive open (as they used a cheep drive, you might be able to use a better reader to determine how far off of the drive baseline the high bits look), and D) all for the measly reward of US$40.
Let's contrast this with a better-run challenge (RC5), it had a faithfully-represented and defined single goal with no restrictions and a reward 250-times larger. From a cracker perspective, any knowledge you have that others don't represents an annuity of income over time for each time you profit from your knowledge, so challenges require large (some would argue for much larger) rewards in order for crackers to forego the annuity and privacy loss.
To improve the Zero-clue Challenge, they should allow people to place charitable bets (maybe using tipjoy) that no one will crack the disk. That should get dollars at stake up, and hopefully to the point where the it will entice someone. They should remove the restrictions in time and access, i.e. pay $100 to play and you get a drive to use how you see fit.