'Jackass Presents: Bad Grandpa' Trailer: Johnny Knoxville Looks Old

"X-Men" spinoff "The Wolverine" was #1 at the box office last weekend, so we know spinoffs can mean big business (not so much the unfairly maligned Elektra, of course).

Two years after "Jackass 3.5," the Jackass crew provides us with a spinoff film starring beloved 86 year-old grandpa Irving Zisman. Of course, Zisman is actually Johnny Knoxville under some Six Flags commercial style old-man makeup. "Jackass Presents: Bad Grandpa" promises to mix secret-camera footage with a fictitious narrative about Zisman on a road trip with his 8 year-old grandson, Billy (Jackson Nicoll).

The brand new trailer suggests the movie will mine hilarity from child endangerment and the general awkwardness of strangers, plus the usual rough-and-tumble pratfalls and whatnot.

All of this got us to wondering: how close to 86 is Knoxville these days? Turns out he's 42! (Hey, Johnny Depp is 50.) "Knoxville" isn't his real name (his birth certificate says Philip John Clapp), but you probably knew that already.

The "Jackass" franchise (are we calling it that?) has generated over $330 million around the world against some very lean-and-mean production budgets. 2002's "Jackass: The Movie" was made for just $5 million.

Speaking of generating, the folks behind "Bad Grandpa" have posted a sweet little gif generator with which you can make stuff to impress your friends on Tumblr.

If this movie is even half as funny as "Bad Santa," it's gonna be great.