“ A portrait of Fran Lebowitz (pictured), taken by Peter Hujar, in 1974, in her childhood bedroom, where it looks as if she just woke up, opens the disarmingly wonderful “Stuff,” a description-defying exhibition at the Pace gallery through Aug. 19. The sculptor Arlene Shechet, who recently proved her curatorial chops in a similarly free-associative show at the Drawing Center, has corralled more than five dozen pieces by almost as many artists, spanning nine decades. (The earliest work on view is a Man Ray photo, from 1934-35, of a weird mathematical model; the newest is a starkly elegant sculpture, made this year by Arthur Jafa.) The tone is intimate, and so is the scale of most of what’s here; one towering exception is a dirty joke in lamp form, by the irrepressible Lynda Benglis. “