Just so nobody gets with the old Looney Toons cartoons, this was a series from around.... 2004, I think, that was on Boomerang. I'd honestly say it's pretty much the closest thing there is to a modern day Animaniacs/Freakazoid. There's a lot of great jokes, a tad bit of action, and even a Green Lantern crossover episode.
Oh yeah, there's an episode where he teams up with Megadeth. Interested yet?
Here's the wiki article! http://en.wikipedia.org/wiki/Duck_Dodgers_%28TV_series%29
And here's the intro. http://www.youtube.com/watch?v=ZpsxfEU-4Is