I purchased the Motorola 68HC11E1 microprocessor and development board through my university for several classes that I have to take. It is essentially a small computer, albeit rather primitive, with an LCD display, breadboard, memory, some switches, some LEDs, serial interface, and a power supply. The 68HC11 family is not built for general computing applications, rather it is meant for embedded control systems, which include everything from elevators to automobile subsystems.

The Single Board Computer
Motorola 68HC11 Closeup
Most compilers for this processor are designed for assembly code, which is very painstaking to develop. However, some compilers allow you to write code in C or C++ and crosscompile it to assembly. Programming in these high level languages is much easier, but in some cases not as efficient.
The best thing about these devices is that you can use them to control just about anything. A microprocessor might only be able to push out a few microamperes of current to an external device, but if you route that through a relay, you can easily control high power devices using this tiny chip. The applications are really endless and that is why these chips are used in so many embedded computer systems, despite having been created about 30 years ago. The 68HC11 series is one of the most popular microprocessors in use, along with the Intel Z80 and a Texas Instruments model.
Buy a Fox11 Board (~$100)
Motorola 68HC11 Assembly Source Code
Related Items:
Wookie 1.68 (68HC11 Simulator Program)