In the Lego-like world of Roblox, about a hundred blocky avatars march through a lamplit street, wielding Palestine flags that are larger than their own animated bodies. Characters dressed like ...

"Sure," we say to Gus. After all, it's a summer weekend. Lucy plops on the family room couch, props the family iPad against a pillow, and FaceTimes Gus on the phone. Together, they dive into a Roblox ...