Curses Epic, you posted it before me.
Since I might as well, one of my favorites would have to be:
Genre: Parody, Action, Sci-Fi
Megas XLR first aired on Toonami in 2004.
The plot started off in the year 3037, when Aliens had conquered Earth and Humanity was at war (straight from the sci-fi plot machine), so in an attempt to end the war, the remaining Earth Forces attempt to send a mecha, named MEGAS, back in time to stop the aliens from attacking in the first place. However, the machine is damaged and the time machine accidentally sends the robot back to 1936, instead of 5 years or so that it was set to go back. We fastforward to 2004 when Coop (our fat, uncool, and clumsy hero) buys the robot from a junkyard for two dollars (two dollars that he didn't pay anyway). He modifies the robot so that it will use a hot rod car for a cockpit, instead of the cockpit the future human forces gave it. He first shows it to his friend Jamie (The "Brock" of the show, lusting for fame, fortune, and girls) who recommends he returns it before someone finds out. Pretty soon, Commander Kiva (The tough hot chick from the future Earth forces) arrives, hoping to locate MEGAS and return it to the time it belongs. She eventually finds the Robot/Car Hybrid, demanding that he return it to her and the future. Before long, the aliens arrive on the scene, fresh from the future, in attempt to destroy MEGAS before it destroys them. This starts the long epic adventure of MEGAS XLR.
The reason this show was awesome is mainly due to the fact that the plot was actually good. It had "Villain of the Week" type episodes where-in they would solve a single plot in one episode. Another reason was the humor. Perhaps a little too mature for it's audience, the show is basically a parody of every action series that involved giant robots (anime, Power Rangers, Zoids, etc.), and what more, it's actually funny. It was also a parody in itself, involving hilarious jokes, funny situations, and really clever jokes about New Jersey. Yet another reason this show is awesome is because, well, it actually WAS awesome. It had fantastic action scenes where a lot of the city would be destroyed.
And as if the show wasn't good enough yet, it has by-far one of the
best intros to a show I have EVER SEEN.
megas xlr intro
And what else to top this off? After a successful 2 seasons, it's canceled. Why? Who knows. Another end to an incredible series of my Childhood.:'(
Now that I think of it, this show really reminds me of Gurren Lagann. The Girl looks the same, the plots are similar, both involving Giant Robots...eh, probably just me.