DrawAnywhere

DrawAnywhere is free software that lets you sketch, annotate, and highlight directly on top of any screen. Great for following along video courses, recording tutorials, hosting presentations, or simply having fun.

Highlights:

Sleek, easy-to-use user interface

50-step undo/redo operations

Stroke eraser toggleable via stylus buttons

Minimal storage usage

Source is available on GitHub: https://github.com/shezik/DrawAnywhere