Rube is a free doodling app that allows users to connect multiple devices and doodle cooperatively over Bluetooth. The app also enables users to cast their doodles on TV, making it a fun activity for family and friends. Rube also offers a game board generator for Sudoku, Loop-d-loop, and Word search, adding an element of challenge to the app. Users can organize their doodles in multiple books and draw emojis on KitKat and later devices. With 200 fonts powered by Google fonts, users can write text in various styles. The app features auto-save and infinite undo, ensuring that users never lose their progress. Rube does not display ads, making it a pleasant experience for users.

It is important to note that the app requires external storage permission to store images and notes. Overall, Rube is a great app for those who enjoy doodling and want to have fun with family and friends.