Under the direction of Tina Landau, Keenan-Bolger and Parsons are predictably fine in their roles, even if they’re not being stretched much. But it’s Lange who commands the evening, displaying the sort of star power and stage command that make her a Broadway diva. Just the sight of her in various outfits, including ‘60s-era hippie denim, is a pleasure, and it’s worth the price of admission to see her launch into disco dancing (the audience, predictably, goes wild). She’s even given a lengthy silent, solo interlude in which she listens to music, has a drink, smokes, and attempts to eat a frozen meal that’s made no less unpalatable by generous doses of hot sauce. Other than conveying the character’s loneliness in her older years, the scene doesn’t have much reason for being. But as brilliantly played by Lange, it’s an acting lesson that every budding thespian should study.