What are some popular children's television shows?

I do not have a television or children, so I have lost touch with what they watch. The last shows I recall are Barney the dinosaur and the Arthur cartoon. When I was a kid, there were a whole slew of shows. I am sure other seniors on the site will recall such shows as Romper Room, Howdy Doody, Wonderama and Rocky and Bullwinkle, just to name a few off the top of my head.