Cartoon Network used to have a show called Dexter's Laboratory and when I was a kid it was something I watched almost religiously. The one thing I learned from this cartoon is how to spell "Laboratory" because Dexter had a thick German accent and always pronounced it "laBORatory", so I never forgot the "o" when I spelled it out.
Aside from my little lesson in spelling, Dexter's Laboratory was just an all-around entertaining show. It's not on anymore but I believe it is still possible to watch it on satellite TV from http://www.directstartv.com/
Dexter's antagonist was his own sister, DeeDee, who was an annoying tween who was always messing things up for Dexter. Anytime Dexter tried to get one of his new inventions out there, DeeDee would do something to destroy his plans.
If I am not mistaken, Dexter's Laboratory was created by the same guy who made Johnny Bravo, American Dad and Family Guy. Yes, Mr. Seth MacFarlane. It's crazy to think he used to make kids shows.