Spongebob Squarepants. This one is pretty obvious. Everyone has at least heard of the show, and it's long had a cult-following amongst all sorts of subcultures. Honestly, at this point, I think they're writing it more for the adults than the kids.
Imagination Station. The kid-friendly boy band guys of this show are like the Wiggles' much cooler older brothers. And they come across as straight, which is just gravy, since one's kinda cute. (He looks a bit like the character Lindsay from "Angel".)
Ni Hao, Kai-Lan. "Dora the Explorer" but Chinese. And with a main character you don't want to punt. (Bonus: Unlike the dangerously unsupervised Dora, the grandpa features as a main character in this show.)
So 'fess up. What are the kids' shows you enjoy, possibly more than your children do?