It’s been exactly two years since Christopher Nolan made box office history with The Dark Knight. Though we’ve known for months that Inception wouldn’t measure up to TDK in terms of grosses, that hasn’t stopped Nolan’s fans from speculating about how much money the director’s follow-up might take in. Well speculate no more! From its 3,792 locations the PG-13 mind-bender took in an estimated $21.3 million, including $3 million from midnight previews.  That’s solid for a non-remake/non-comic-based property and well above the $14 million Shutter Island made on its opening this February. But that’s not a fair comparison. In fact, because of Nolan’s reputation and his insistence on keeping his film’s concept under wraps, you would have to look all the way back to August 2002 for a film that feels comparable. Back then a hot director named ‘Shyamalan’ opened Signs with $20.8 million on Friday on its way to a weekend worth $60 million (not adjusted for inflation). As with everything concerning Inception, weekend projections have been all over the map; but I’m guessing that $60/$65 million is about right. We’ll have details tomorrow.