Disney's Little Einsteins has been out of production since 2009, but continues airing 7 days a week on either Disney Junior or Disney Channel. Two seasons were produced over a span of 4 years (2005-9). Don't ask me why, 'cause I don't know.
Curious Pictures, the folks that brought you Codename: Kids Next Door for Cartoon Network, moved down the scholastic ladder with this show, aimed at preschoolers, but still imbued with plenty of adventure as well as learning.
Here's the open:
There are DVD compilations to be had, if you want to keep your preschoolers entertained any time of the day.