Unfortunately, I believe they took the little kiosk away with all the free clothes. I didn't see it there the other night.
The participation item is still available (girls only this week) until the end of the day, but we have the 14 hour maintenance starting at 3PM EST so you have until then to get it if you want the backpack for a female avatar.
But there will be a new participation item for WW starting tomorrow. Not sure what it is yet.