After five two-hour audition shows, it was down to the final 20 performers who will vie for the title and $250,000 on the fourth season of "So You Think You Can Dance?" After a topsy-turvy intro in which each of the finalists got a few seconds to show off their moves (Dramamine, anyone?), host Cat Deeley laid out the process: the top 20 will be split into 10 couples and each week theyll pick their dance styles randomly out of a hat. Theyll perform and the voters pick their favorites. On Thursdays, the three lowest vote-getting couples will be announced and those six dancers will perform solos before the judges decide which guy and which girl is going home.Guest judge Dan Karaty joined Mary Murphy and Nigel Lythgoe for the first episode. And were off!