Kaizoku Sentai Gokaiger is the 35th season of the Super Sentai franchise, celebrating the 35th anniversary of the franchise as well. It ran from February 13, 2011 - February 19, 2012. It succeeded Tensou Sentai Goseiger and was succeeded by Tokumei Sentai Go-Busters.
Why It Rocks
The Gokaigers morph into several past Super Sentai Rangers, which really works for an anniversary season of Super Sentai. Even their respective seasons' theme song played out during their Gokai Changes.
The Gokaigers are very likable and they have very distinct personalities and motives:
Captain Marvelous (GokaiRed) being the leader and the most serious and reckless of the team.
Joe Gibken (GokaiBlue) being the brains and the most sympathetic of the team.
Luka Millfy (GokaiYellow) being the most adventurous, cute, and greedy of the team.
Don Dogoier (GokaiGreen) being the most incompetent and cowardly of the team.
Ahim De Famille (GokaiPink) being the friendliest and the calmest of the team.
And Gai Ikari (GokaiSilver) being the only earthling and the comic-relief of the team.
It is so far, the only Sentai season that uses pirates as a theme.
Emperor Ackdos Gill and Basco Ta Jolokia are super intimidating threats to the Gokaigers.
The Gokaigers have very interesting backstories, especially Gai.
Spawned several Ranger Key toy sets for the fans to collect, and even Bandai released more Ranger Keys (even Metal Heroes) after the show's run until Zyuohger or the upcoming Zenkaiger.
Some episodes even bring back some actual past Sentai rangers! When the ranger reveals which ranger he is, a "Legend Shift" occurs where a brief image of the ranger shows. This shows that a lot of thought went into the creators to execute the anniversary season. Notable examples include: