These are links to different people's sites that I find interesting. Uncategorized and Unsorted

http://www.retrochallenge.org/ : Internet contest that runs about once every 6 months. I participate when I can.
http://gkanold.wixsite.com/homeputerium : Internet contest that runs every year. Can you write a game in 10 lines of BASIC?
http://www.retrotechnology.com/ : Herb Johnson's retrocomputing page. There is a lot of good COSMAC RCA 1802 information here, including a good assembler written by William C. Colley, III.
http://commodorez.com/ : Various projects, including the Cactus 6502
https://gigatron.io/ : TTL Microcomputer kit
http://obsolescence.wixsite.com/obsolescence : Various retrocomputer recreations, including PDP-8, PDP-11 and Micro-KIM
http://sarrazip.com/dev/cmoc.html : A very good C-like compiler for the TRS-80 Color Computer. It is similar enough plain C mostly compiles with little to no fuss.
http://www.codercorner.com/Coder.htm : Pierre Terdiman ( Seems to have more updates:http://www.codercorner.com/blog/ : )
http://www.sparkbangbuzz.com/ : Nyle Steiner has several very interesting electronics projects, including homemade diodes and triodes.