Despite the fact that Gilbert and Sullivan premiered “H.M.S. Pinafore” in 1878, the Yale Gilbert and Sullivan Society’s rendition of the play, which opened last night and runs through Saturday at the Off Broadway Theater, is pretty damn funny. Don’t get me wrong: it’s dorky and lame and makes you feel very silly for laughing at it, but it’s funny nonetheless. The show succeeds in both paying homage to and mocking the original text; it is a veritable celebration of Anglophilia in its earnest and ironic variations.

The show, which features a small orchestra directed by Spencer Cromwell ’12, focuses on the crew of the title ship that is pretty much what you would expect from a British musical that premiered in 1878: the sailors are merry, the maids fair, the social classes mercilessly stratified. The action of the play is precipitated when Sir Joseph Porter, K.C.B. (Austin Case ’11), a bigwig in the “Queen’s Royal Navy” (even though he has no actual Navy experience), visits the Pinafore with the expectation of wedding Josephine (Catherine Leech ’11), the beautiful daughter of Captain Corcoran (Ezra Marcus ’10). Little does he know that Josephine is already in love with Ralph Rackstraw (Jack O’Reilly ’12), a petty seaman aboard the Pinafore.

The action is pretty straightforward (SPOILER ALERT: love triumphs over class conflict, everyone gets married at the end), but directors Isaac Durand ’10 and Arden Rogow-Bales ’10 are able to craft the humor in the play so that the jokes are updated to be funny to a modern audience while maintaining the sensibility of the original. Sir Joseph Porter’s snooty, bureaucratic blathering was funny in 1878, and it’s still pretty humorous. On the other hand, Captain Corcoran’s self-consciousness is decidedly contemporary — he could have come straight out of the latest Judd Apatow movie. There is surprisingly little clash between the two senses of humor, and they often meld quite well. The sailors’ merry songs are amusing to a contemporary audience because there is something hilarious about their obliviousness to the sexual tension present in such a clearly homosocial space, but they’re also funny because being silly is fun, independent of the century. For all the talk about how humor doesn’t age well, the cast of “H.M.S. Pinafore” succeeds in showing that what counted for “humour” more than 200 years ago, is still “humor” today.

It’s that earnest exuberance that makes the show worthwhile. Sure, the cast takes jabs at themselves every now and then, but their enjoyment of the source material appears to be genuine. Theater is art, but there’s something to be said for walking into a theater and getting a good time without having to think that hard. “H.M.S. Pinafore” is just that; it doesn’t demand anything of its audience except that we dispense with our pride and preconceptions and simply enjoy the show — the actors’ zeal is so infectious that even that isn’t a chore.

Whether you’re a fan of musicals, you love Gilbert and Sullivan (I, I must admit, had never heard of them before) or you have nothing to do and want a laugh, head over to the OBT this weekend. Who knows? “H.M.S. Pinafore” might just be your cup of tea.