Take an evening and hang out on the website directly - don't wait for the email. Keep refreshing the page that has available dates at the site you want. Spots seem to open up a few days/weeks beforehand - perhaps people who are rescheduling last minute? Hang out in the evening with your computer, just keep refreshing and something should pop up that will fit. I've heard that Friday or Saturday evenings seem to be good for this, but this is all hearsay! Good luck : )