This may be a nuisance to a lot of people, but I think it would be good service to the community to have a sitewide notification about when the open call for Superstar items closes. I'm picturing that Wikipedia style "If everyone on the site now donated five bucks we could get so much pizza" things on the top of the site that collapses after a brief moment or when you start scrolling. I have no idea what to even google to find out that mechanism's name. Also, maybe give it a 'do not show me this notification' checkbox and cookie or whatever. Let people unclutter as needed.
I like this idea! I'll add it to our list of things to improve for next year's contest.
I did that thing this year where I decided to enter the Open Call exactly five minutes after it closed. :(