Field Programmable Gate Arrays
FPGA's are programmable and very flexible devices. Most of them are based in RAM switches which connects logic elements to form the descrived hardware in vhdl or verylog.
Some time ago I designed an FPGA developement board based on an Altera EP2S60 device. On the board there's the minimum, the FPGA some linear power supply, a PIC microcontroller to configure the device on power up, a flash memory to store the code, a USB to FIFO (FT245RQ) converter connected to both microcontroller and FPGA, and finally some buttons, led's and a lot of pad's connected to devices I/O's. You can see a picture of the firs version just here. The final board is around 90x75mm.