Yes. And there are seasonal challenges now, though I'm not sure how many they plan to have. The current one (listed for Summer 2011) is 'Bees Hate You':
-For every 'b' in your equipped items, take 10% damage.
-You can't use most items with a 'b' in them. (this is the Brutal part)
-Bee-based enemies will attack you every set amount of turns.
-And other, more spoilery stuff.
I'm a level 5 Disco Bandit, so I kind of dropped the ball on this one.
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As an aside, they really killed the purpose of HC-perming, since you no longer have to do any HC runs to HC-perm anything.