Teachers have a very specific set of constraints that most web apps ignore: locked-down district Chromebooks, no permission to install anything, strict student privacy rules, and about five minutes between the bell and needing a tool on the projector. Badge Your Classroom is a set of 24 free, browser-based teacher tools — wheel of names, timers, bingo cards, word searches, crosswords, a Jeopardy-style review board, a noise meter and more — built around those constraints. Here's what buildin...