When Malcolm and Mandy Sim welcomed two children into the world, the veterans of both the animation and theme-park industries visited numerous indoor play centers in Los Angeles, hoping to find the one that best suited their kids. Nothing quite clicked, however, which inspired the parents to call upon their entertainment backgrounds and develop their own indoor facility. Since relocating to the Boston area, the Sims have opened Jam Time, where youngsters ages 3 months to 6 years can surmount climbing structures, leap about in a bounce house, or shop in a pretend grocery market before whipping up faux soufflés in the playhouse kitchen. Classroom sessions further engage tykes with art projects, science classes, and princess-etiquette lessons, where young ladies learn to detect whether evil witches have booby-trapped their science projects. Soft play toys engage visiting toddlers and infants, while adults surf free WiFi, sip gourmet coffee, or enjoy a treat from the organic snack bar.