Attiny84 microcontroller is pretty small microcontroller. But Jack Eisenmann decided to invest some time in making it in to programmable device. For this he built a simple computer with external 64KB EEPROM for storing programs. Since everything has to be very compact he created a speciffic programming language called DTPL (DUO tiny Programming Language). It is nothing more than a command followed by set of arguments.
Jack also wrote a tiny operating system which allows writing own programs using four button interface, change settings, playing games and more. Computer uses a 102×64 pixel LCD to output information. This can be turned in to great small computer to teach kids programming.