Matt Kahler (Major General) and the cast of The Hypocrites' “The Pirates of Penzance.” (Evgenia Eliseeva)

What the Chicago-based troupe the Hypocrites have done with Gilbert and Sullivan’s “The Mikado” and “Pirates of Penzance” is turn both into irresistible parties. “The Mikado” is a carnival, while “Pirates” is a beach blowout.

In both cases the exuberance is engulfing. As soon as you enter the Olney Theatre Center’s ­Mulitz-Gudelsky lab space you’re amid strolling musicians skipping and hopping as they play pop tunes. The Beach Boys’ infectious “Sloop John B” launches “Pirates,” so sing along. Smack a balloon or a beach ball into the air. Hit the little bar in the corner: It’s open throughout the show.

Adult beverages notwithstanding, these are intensely kid-friendly events. The spirits are preposterously high on the playground-like sets where a substantial portion of the audience sits — until, that is, they’re nudged aside by the crazily costumed actors. The ultra-friendly Hypocrites are so good at loosening up a room with their atmospherics that you may wonder: why bother with “The Mikado”? Why trifle with “Pirates”?

Gilbert and Sullivan buffs will either love or hate these high­concept and super-fast shows, each an 80-minute blitz through the beloved operettas. (They are running in rotating repertory.) You could attack the productions for the breakneck pace and for the anarchic, antic style that at times can feel relentless, and that occasionally overwhelms the puckish satirical and pun-laced lyrics that Savoyards revere. Seriously, if you’re not interested in being on a playground, these shows won’t work.

The exuberance is catching, though, and the rep surely rates as among the most carefree and joyous events D.C. theater has served up this long season. Musically there is a lot of ingenuity in adapting the late-19th-century scores to a small army of mostly stringed instruments: lots of guitar, plus ukulele, mandolin, accordion, fiddle, flute, even toy piano and (quite beautifully in “Pirates”) a musical saw. The humor is frisky in these orchestrations: in “The Mikado,” the notoriously homely love interest Katisha — here referred to with comic dread as “the jazzy Katisha” — plays saxophone, and the riff she blasts entering and exiting is cribbed from the 1970s hit “Baker Street.”

Andra Velis Simon’s musical direction makes the troubadour style look deceptively simple. When the trio of ladies enters singing “Three Little Maids From School,” one of the women is skilfully plucking a banjo. In “Pirates,” Matt Kahler zips through the famously rapid lyrics of “Modern Major General” while strumming a guitar. Offbeat? Decidedly, even if Gilbert and Sullivan have been adapted 10 ways to Sunday over the years (the swing jazz “Hot Mikado” being one of many variations). The actors sing well and play lots of different instruments with aplomb while cracking contemporary jokes: “Let me man-splain this,” the Pirate King (Shawn Pfautsch) says at one complicated point. The shows feel like the giddy result of a major music camp mutiny.

The cast of the Hypocrites' “The Mikado” at Olney Theatre Center. (Anna Danisha Crosby)

Hypocrites ringleader Sean Graney directed and adapted both productions, which premiered in Chicago several seasons ago. (Kevin O’Donnell co-adapted “Pirates,” and also designed the sound.) Graney easily sidesteps the dicey cultural appropriation issues that have recently bedeviled other stagings of “The Mikado” by wiping Japan right out of the show. The opening chorus of “We are citizens of Japan” has been changed to “We are citizens of this land” — a land that is apparently a freewheeling carnival.

“Pirates” looks like it’s rooted in 1978 or thereabouts, what with tight little disco-era shorts and tall tube socks dominating Alison Siple’s costume design. Tom Burch’s set for “Pirates” includes kiddie pools and maybe a dozen coolers strewn through the area. Sit on one if you like, but be ready to move if a cast member points at you.

So, can this cast of 10 act? It’s not that kind of show. It’s a street performance: They entertain with bright music and broad gags, wiggling the huge fake mustaches under their noses when four of them play bumbling policemen in “Pirates,” or dashing in and out of costume to play two parts, as Pfautsch does handling “The Mikado’s” mandolin-strumming Andy-Poo (changed from Nanki-Poo) and the sax-blowing Katisha, or as Kate Carson-Groner does doubling as the aged Ruth and the young banjo-playing Mabel in “Pirates.”

You get the picture. Seek no substantial dramatic purpose here; if any such thing exists, it’s lost in the wash. What the Hypocrites are offering couldn’t be more transparent, or more necessary: a high tide of good times.

“The Mikado” in rotating repertory with “The Pirates of Penzance,” music by Arthur Sullivan, words by W.S. Gilbert. Directed and adapted by Sean Graney; “Pirates” co-adapted by Kevin O’Donnell. Co-directed by Thrisa Hodits. Lights, Heather Gilbert. With Mario Aivazian, Eduardo Xavier Curley-Carrillo, Brian Keys, Amanda Raquel Martinez, Tina Muñoz-Pandya, Dana Omar and Lauren Vogel. Through Aug. 21 at the Olney Theatre Center, 2001 Olney-Sandy Spring Rd., Olney, MD. About 80 minutes each. Tickets $38-$65. Call 301-924-3400 or visit