Hayate no Gotoku (Seasons 1 and 2): A
Main character with the blue hair on the left. The three in the foreground are the fun ones.
Hayate no Gotoku (Hayate the Combat Butler, is the English title) is a highly referential comedic anime about a very unlucky young man named Ayasaki Hayate, who possesses a pair of superlatively awful parents, and is forced (through a series of circumstances in the first two episodes) to become a butler to the astoundingly rich Sanzen'in Nagi, a 12 year old heiress, otaku and hikikkomori, who thus far has only lived with her young maid Maria, the head butler Klaus and her pet "cat" Tama.
Nagi's eclectic lifestyle and friends and classmates and Hayate's adjustment to the world of the absurdly rich are played for laughs (as is Hayate's incredibly bad luck), and a number of Shonen traditions are ruthlessly mocked (there is a 2-episode Tournament arc, and a period where other butlers are coming to challenge Hayate occurs in a two-minute segment at the end of every episode).
As much as that is the plot of the story, such as it is, the show has a fairly large and colorful cast and spends more of its time making japanese pop culture and anime references and hanging lampshades than it does advancing its wacky Love Dodecahedron "plotline".
The first season is a 52-episode series and focuses on the humor, anime referencing and random silliness. For someone like me, who takes supreme enjoyment in playing "spot the reference," the first season is solid entertainment. The second season begins with a soft reset (unexplained, but fairly obvious to anyone who's seen the first season) and focuses more on romance and relationship development, without abandoning the absurd humor.
It's a very Japanese series, and while I say that with a lot of affection for it, it is something that I would use to warn a lot of casual viewers. If you're unprepared for machine-gun references to an unfamiliar culture, Hayate no Gotoku will be a little be a little overwhelming. Not incomprehensible, but you'll have a constant feeling of "There was a joke there that I should have gotten..."
While the plots are often utterly ludicrous, the characters are extremely lovable, often being extremely competent in one area and extremely incompetent in another at the exact same time (I would posit that that is the theme of the series: the humor inherent in human flaws), and the show jumps between heartwarming moments of friendship and loyalty and snappily-delivered textual and physical comedy. Overall, it's a positively wonderful show for anyone interested in romantic comedy, with a giant pile of bonus material for the dedicated anime watcher.