It currently only has three challenges that work, so if you can complete those (WITH PROOF ) then I will give you a cookie. The challenges alternate between duels and random stuff. Use the door on the left to enter a challenge. Don't enter the first door on the right or you lose. No really, you lose.
If you need help on challenge #2, post here and I can help you in spoilers.
SCREENZ:
In the Instant Action screen, it'll show up as "Boss Battle Extreme." I haven't gotten around to changing it yet. It's yellow.