If you've ever seen a movie where they show a much younger or older version of one of the main characters and thought, “that actor really looks like he could be the other person at another age,” then you'll enjoy the blog Kidcasting.
3It's Always Sunny In Philadelphia
Charlie Day as Charlie Kelly, Rob McElhenney as Mac, Glenn Howerton as Dennis Reynolds and Kaitlin Olson as Sweet Dee Reynolds.
4The Sarah Silverman Program
Sarah Silverman as herself, Laura Silverman as herself and Andy Samberg as Andy, Sarah's imaginary friend.
5Tenacious D in The Pick of Destiny
Jack Black as JB and Kyle Gass as KG. (Creative names, guys.)
6Austin Powers In Gold Member
Mike Myers as Austin Powers, Mike Myers as Dr. Evil and Robert Wagner as Number Two.
7Hot Tub Time Machine
Rob Corddry as Lou Dorchen, John Cusack as Adam, Craig Robinson as Nick Webber and Clark Duke (who doesn't change) as Jacob.
10Bill & Ted's Bogus Journey
Alex Winter as Bill S. Preston, Esquire, and Keanu Reeves as Ted Logan.