Believe it or not, Diablo is turning 20 years old on December 31st. Yes, the classic clickfest has been around for long enough that some adults weren't even alive when the first game launched. It's a historic moment for gaming -- and Blizzard is marking the occasion by bringing Diablo-themed events and extras to several of its games. Diablo III, unsurprisingly, gets the most lavish treatment. It's going to get a Darkening of Tristram event that lets you visit a "reimagined" version of the original game's cathedral, including some familiar pick-ups.