Often overshadowed by his television fame many people are not aware of Whedon's involvement in children's animation.
Any of these ring a bell:
2001 - Atlantis: The Lost Empire (treatment)
2000 - Titan A.E. (screenplay)
1995 - Toy Story (screenplay)
Even if you weren't aware of his invovment chanses are these movies struck a cord in you young life. It may have been the likable characters, the catchy dialog, or the inspired setting that turned you on to these movies. Little did you know that it those same qualities would make you fall in love with Buffy or Firefly or Dollhouse.