I remember hearing a lot of buzz around the time Sgt. Frog hit Japan many years ago. But it took some time for Funimation to make a English dub which is now on Netflix Instant. Once I saw it on there, I was hooked.
The series is about a frog-like alien named Keroro who is a sergeant on planet Keron. He plans on taking over Pekopon (their word for Earth) but his dreams are halted when he is caught in the Hinata family home. Keroro eventually just becomes their lazy house-servant who randomly motivates himself to complete his mission. Unless he gets a new Gundam model.
But Sgt. Keroro is not alone, he eventually gets all the members of the ARMPIT platoon back together. The first is the cute but insane Pvt. 2nd Class Tamama who lives with the super-rich human girl Momoka who happens to have a severe-crush on Keroro's human friend/owner Fuyuki Hinata. Then they reunite with the hot-headed weapons expert Giroro, and then the sadistic and wacky genius Kururu. The last member is the ninja Dororo who brings the squad together with his love for Earth.
Sgt. Frog is not the typical action-anime, but rather more like a comedic sitcom. Keroro and his frog pals are goofy, and the Hinatas and other human characters are almost as wacky. Plus a narrator who make sarcastic comments about the story plots and lack of happiness at his job makes this one of the funniest shows I've ever watched.