Four guys are playing piggyback in this clip from Bob Mizer's 1965 short film "Seven Athletes."
Editor's note: Larry provided the names of Brian Idol, Jim Horn, Jim Barkley, and Sam Hunter as being in the film, but not necessarily in this clip. I definitely recognize Brian here.
Added: See the_cham_cham's comment below for some ID info.
Many thanks to Larry for yet another great guest series!