Well, if no one else mentions that it's Sysadmin Day, maybe you should remind your boss or hang a sign on your cubicle -- something like "Be nice to me for a change. It's Sysadmin Day for crap's sake." Maybe someone will notice and begin to think about all the ways your work enables their work.
Or maybe you can kick off a tradition by thanking some other sysadmins (database admins and network admins count too!) or taking some other admins to Happy Hour after work. Or you could actually take a real lunch break for a change -- instead of eating at your desk.