Keynoter Chris Christie and the other speakers at the Republican National Convention have been confirmed, but there's still a "big surprise" in store, according to Donald Trump. "Today I am working on my 'big surprise' for the RNCconvention," he tweeted yesterday. "Everyone will love it." Last week, he claimed he had turned down an invitation to speak at the convention, notes not-a-Trump-fan Alex Pareene, who shares his best guess on what the "big surprise" might be at Salon: "some idiotic video where Trump 'fires' an Obama impersonator." (More Donald Trump stories.)