I remember fondly of many commercials shown during after-school hours, mostly on Fox Kids and whenever WWF is on at the time Here are some of my favorites:

-Legend of Zelda: Ocarina of Time (N64)
http://youtu.be/JntHVUp7m4E

-Donkey Kong Country 2 (SNES)
http://youtu.be/91cc0RSN3zU

-Final Fantasy III (SNES)
http://youtu.be/d15qmRzn2Pc

and one more for now ~

-Final Fantasy 10 (PS2)
http://youtu.be/OpSWxpP9DKI