Inspired by http://tinkerlog.com/2009/04/05/driving-an-led-with-or-without-a-resistor/ I started to build a USB driven display. I ordered some big green 5×7 dotmatrix display fromhttp://evilmadscience.com/ and had a look at v-usb.
What you get when combining those is a via USB controllable dotmatrix display. The PC related programming I did in Python using libusb and the python binding called pyusb. So the program should be cross platform compatible! Also python allows one to extend the functionality(e.g. checking for new mail, usb notifications of any type…) very easy.