Blackboards are what I grew up with at school although nowadays it's all about fancy whiteboards and computer screens.
Ardoise is a old style blackboard that allows you to write, draw and erase whatever you want. When you launch it, Ardoise remains hidden as a transparent small version which is called "Hide mode" and when you want to draw, just switch to "Draw mode" and you can use Ardoise just as you would a normal blackboard but with virtual chalk.
It can even "remember" different boards for different days of the week - so you can set a reminder board for every day of the week. You can also highlight the most important things in different colors. There's even a small syncing tool which allows you to upload your Ardoise board to an FTP server for downloading on another device later.
Blackboards don't come much more sophisticated or useful than Ardoise although it would have been nice to see it incorporate reminder alarms.