The longest-ruling, most ingeniously constructed, most endlessly playable quiz show of all time? What is Jeopardy!, Alex? Jeopardy! is the hardiest survivor from the old-school game shows (though many of us carry a torch for Charles Nelson Reilly-era Match Game and Paul Lynde-era Hollywood Squares), hosted by the dapper, though no longer mustachioed, Alex Trebek. You can still play along every night.