In 2004 the banners were random and there were fantastic free prizes. You have to be quick because sometimes there are only 1 or 2 free prizes for that specific product. In 2005 there were no free prizes from what I remember just great discounts. From what I've read and seen on the Sideshow website this year is shaping up to be larger than the 2004 event.
The fun part is staying up into the weee hours of the night to catch that elusive free item that most only read about the next morning on this board.
There are usually a ton of giveaways that require answering a trivia question or following clues to the correct product. Sometimes the Mistress gets sneaky and hides questions on the site with no clues and you have to search for days to find them. It's one of the most fun events Sideshow puts on next to Fantacular, Toy Fair, and Comic Con.