I picked 37 ... Double digits made me think of a number in the 20's, went for 30's when it said that both numbers had to be odd, and must have went for 37 since 7 is such a popular number - neat little "illusion".
I think the trick was to get you to waste your time looking at this thread. While you were looking at the thread, someone was stealing your wallet.
13 <object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/pv9nleiFogc&hl=en"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/pv9nleiFogc&hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>
There's only eight numbers to choose from when you think about it. It's said that way to make it seem like the person is guessing from a whole bunch of numbers.