If you’ve ever thought about getting down to bare metal and building a homebrew computer from scratch [Garth Wilson] put up a great primer to the 6502, the same CPU found in Apple ][ computers, BBC Micros, Vic-20s, and the venerable Commodore 64 (a 6510 in the C64, but it's close enough).
In his guide to building a 6502 computer, [Garth] goes over all the basics – what you want the computer to do, how to decode addresses, and other important technical requirements for getting a homebrew project running.
If that’s not enough, [Garth] directs his readers to the fabulous 6502.org forums where just about every topic is discussed. The guys on the forum have a standardized I2C pinout for the 6502, allowing noobs to easily connect pre-designed keyboards, displays, and storage devices to their projects. There are a ton of tutorials on the 6502.org site, more than enough to get a homebrew project off the ground.
If you’d like to see what you can do with a homebrew 6502, check out the homebrew projects page featuring a 6502 Nixie clock and CLPD-based 65816 single board computer. There’s a treasure trove of information here, just waiting to be pulled from the vine.