Willow and Batman are the same age - they're both 40 years old. Let that sink in - the weird nerdy girl-turned-RenFaire cosplaying witch and Bruce Wayne are somehow both officially middle-aged.
Matt Smith was the youngest actor to ever portray the Doctor, beginning his tenure at age 27. Now both he and Seth Rogen are about 32 years old - which seems a bit young for Rogen too, but keep in mind he started his career on Freaks & Geeks when he was 17.
It's hard to think of Gene Wilder as old - he disappeared from the movie world (for the most part) decades ago, so the picture most people have in their head is the young, lively guy in Willy Wonka and Young Frankenstein. But in reality he's as old as Michael Caine - both will be 81 by the end of the year.
Jim Carrey is 52 years old. This is one of those "wanna feel old" moments, I guess - but the guy still looks pretty good for his age. Still, it's pretty shocking he's the same age as PC gaming duke Gabe Newell. And since Gabe was born in November and Jim was born in January, the reality is that Gabe's almost a full year younger than everyone's favorite butt-talker.