Test your mental might!

Thanks to Kabitizin and Velius for pointing out this interesting brainteaser. I got 15/33 (1-3, 7, 12, 18-19, 21, 23-25, 27, 29, 32), which apparently puts you into the "intelligent" category, but as Kabitizin said, this test is hardly a comprehensive test of your intelligence. Answers are posted on Kabitzin's site here.