Twice a week, I update the science writing status report. I would like to say that I do this biweekly. In fact, I do say that, but every time I say it (which, I admit, is not often), I always curse the fact that biweekly means twice a week or every two weeks. And I don't think that semi-weekly is a real word and even if it were, it sounds weird. Words that mean the opposite of themselves should be illegal.