I went today. It was really mainly a kids' event.
From what I saw, a couple of color-ins, then they wrapped each other in toilet paper to do a mummy dress-up and tore it off. Then it was trick-or-treat which was basically following staff around the store to collect various candy that you got to keep (this one was mandatory if you wanted to get anything). Everyone whom participated got a certificate.
There was a free raffle to win a copy of the Ghouls Rule DVD (which I thought was a great idea) and then the 'gift' - rubber Monster High wristbands and a Ghouls Rule flyer - were given out.
All in all it was pretty good, better than Walmart.
I'm surprised there was no smaller stationary given out such as stickers tho. There weren't any sales on Monster High either, everything was still full price, which I thought a bit odd for a promotional event. I kinda found it tiring to stay around the whole time to get what I had registered for though it was a great occasion for the young kids.