Source: Legion of Super-Heroes animated series (2006-2008)
Type: TVIn a universe where Clark Kent went straight from Kansas farm boy to world's greatest hero, when did he find the time to train? The Legion cartoon show answered that question by having the 30th century super-team snatch him from a point just before he left home for Metropolis, and giving him a place to hone his powers for a few months (Season 1). After Ferro Lad's death (that's not a spoiler, that's inevitability), they return him home in time for dinner. Season 2 takes places a couple years later (in both time frames), with Superman now a lot more buff. Cue female Legionnaires going squee.
Well he wasn't going to stay a big-eared geek all his life.
So why Superman and not Superboy? It would seem this series was born right in the middle of the Superboy litigation and the name wasn't really available (or at least imprudent). It does make for an interesting take on the Clark in the Legion story, one I'm surprised wasn't pursued in the actual comics when they started retelling Superman's origin again and again. The Legion as Superman: The Hidden Years. Works for me better than his walking the Earth à la Bruce Wayne.