When the thermometer closes in on the century mark, wise New Yorkers head north. I recommend a day trip to the Hudson Valley Shakespeare Festival to see Terrence O'Brien's joyously dotty outdoor production of "A Midsummer Night's Dream," staged in the style of "3rd Rock From the Sun," complete with space invaders and a flying saucer. Mr. O'Brien, the festival's founder and artistic director, isn't overly concerned with thematic consistency, and his "Midsummer Night's Dream" also contains such interpolations as a dance routine choreographed by Lisa Reinhart in which Titania (Nance Williamson) leads the cast in a frenzied mambo, lip-syncing to the music of Yma Súmac, the mad diva of Peru.

Don't let any of this scare you off: It's all funny, and Mr. O'Brien's cast hurls itself into the maelstrom with happy abandon. I was especially taken with Susannah Mullonzi's spitfire Hermia, Ms. Williamson's sexy Titania, Wesley Mann's cartoony Puck and Paul Bates's anything-for-a-laugh Bottom (I loved it when he sang one of his songs to the "Gilligan's Island" theme).

The production, which runs in rotation with "The Rivals" through the beginning of September, is performed on the grounds of the Boscobel Restoration, an early-19th-century mansion perched on a wooded bluff overlooking the Hudson River. It's the prettiest outdoor theatrical setting I know, and Mr. O'Brien, as always, makes the most of it, flooding the trees with magenta light at evening's end and allowing the silliness to dissolve as if by magic into pure poetry. He likes his laughs, but he knows when to get serious, too, just like Shakespeare.

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Mr. Teachout, the Journal's drama critic, blogs about theater and the other arts at www.terryteachout.com. Write to him at tteachout@wsj.com.