Aspiring screenwriters don't have many great choices for simple, purpose-built apps: What exists is frequently expensive, overkill or both. Amazon may shake things up with its new Storybuilder beta, though. The free web app lets auteurs outline movie and TV screenplays using a virtual corkboard accessible from any device with a modern browser; if you think of a clever plot twist while on your phone, you can drop it in. Writers can add images, notes and tags, and they can invite critiques from other readers. Storybuilder won't replace a full set of scriptwriting tools, but it and the existing Storyteller app may get the ball rolling on your next big drama.