Blue's Clues launched in 1996 on Nickelodeon as part of what was then a morning block for preschoolers, before Nick Jr. was spun off into its own channel. Steve Burns was the clean-cut, genial host for the first six seasons (1996-2002), guiding young viewers through the everyday life of Blue, an animated dog. After Burns left, Joe (Donovan Patton) took over for the final 2 years of original shows, as production ended in 2004, though reruns would continue for another 3 years after. Blue's Clues also spent some time on CBS as part of its Nick-centric Saturday morning block.
Here's a sample episode, courtesy of Dailymotion: