http://www.theregister.co.uk/2015/06/23/brit_mega_processor/
A bloke in Cambridge, UK, is building a computer processor using 14,000 individual transistors and 3,500 LEDs – all by hand, piece by piece. James Newman said his Mega Processor relies almost entirely on the hand-soldered components, and will ultimately demonstrate how data travels through and is processed in a simple CPU core. He's just finished putting together the general purpose registers, and in May completed the arithmetic and logic unit.
Each transistor acts like a digital switch, and can be chained together to form huge decision-making circuits that execute software, instruction by instruction.
The finished circuitry, when mounted on a wall of boards, will measure 14 metres long and 2 metres high (46ft by 6.6ft), will weigh about a half-ton, and will consume 500W. he now fears he won't be able to fit it all in his home.
Newman, whose background is in software development and FPGA programming, told The Register he has spent about £20k on the project to date. He started planning the processor in 2012, and began building the beast a year later.