Make/hack some hardware
Midibox.org TK’s non-commercial, custom synth project. Open source hardware and software at its finestIf you want an MB6582 – go here. Bring your soldering iron though.
8-bit Ventures Home of the Prophet64, MSSIAH and SID2SID. Turn your crusty old C64 into a 303, drum machine or wicked synth or wave player. In stereo!
C64DTV Hacking Wiki C64DTV Hacking Wiki – A wiki on modifying your plug-n-play C64 Direct-to-TV.
AlphA's Site AlphA – the godfather of C64 mods. Check this site out for how to do all that modding stuff.
Prophet64 Forum Forum for the unstoppable MSSIAH cart for the C64. Good place to go if you are stuck with a mod, after ideas, or want some good feedback on your chiptunes.
ModRetro Forum Console hacking forum. For all that nintendo, atari, playstation, sega stuff. And more.
Arduino The Arduino: the open source hardware controller. You can make it do anything!
Making Things Making Things. Home of the Make controller. Another hardware controller with all sorts of ins and outs. Heavy!
Making Things Mini-ITX.com – you can put a tiny PC into just about anything. I put one in a C64 case – this is where I got the motherboard.
Thingiverse Thingiverse – Community of people fabricating stuff. Awesome!

64 hardware + peripherals
1541 Ultimate 1541 Ultimate page. Gideon’s Genius 1541 emulator – load D64 files off a MMC card. I have one.
C64TPC C64TPC – Use your PC as a disk drive.
Fotios' site Fotios develops new hardware for the 64. What a guy!
Fotios' site The Keyrah – an interface that will enable you to use a Commodore keyboard as a PC USB keyboard. Shortcut to making a C64 into an Ableton Live controller if ever I saw one…
CMDweb CMDweb has a whole range of crazy new C64 hardware. I hear these are hard to get hold of. Good for a look around if anything.
1541-III Home of the 1541-III – a SD card disk drive solution.

Circuit Bending
Casper Electronics Casper Electronics – Genius toy & synth circuit bending hub. Home of The DRONE LAB – an all analog, open source drone synthesizer, rhythm generator and FX processor.
Circuit Benders Circuitbenders.co.uk : “offering circuitbent machines for sale, alongside a wide range of custom modifications and upgrades for electronic toys, drum machines, synths and samplers.” Nice!
Experimentalists Anonymous Experimentalists Anonymous: Great circuit bending site / blog
GetLoFi GetLoFi: Circuit Bending tips and resources for Beginners and Pros alike.

Synths + Blasters
Matrixsynth Matrixsynth is a fantastic blog. If you love synths, watch it. Wear a bib though.
Stereo2Go Stereo2go – Community of Ghetto Blaster enthusiasts
Ghettoblasters on ebay Ghettoblaster search on ebay UK. Solid.

Software
High Voltage Music Engine Collection High Voltage Music Engine collection. A whole heap of 64 synths and software.
C64 Codebase C64 Codebase on SID programming. If you want to get down and dirty programming for the SID chip on the C64, this would be the best place to start. Lots of code examples.
CCS64 CCs64: The most reliable C64 emulator you’re going to find.

DIY Game systems
XGameStation XGameStation do a range of custom DIY game consoles.
Adafruit Adafruit – custom kits & stuff. Includes the Fuzebox – a fully open-source, DIY 8-bit game console.

General + Extra
Make Blog Always great stuff on here. For makers and hackers.
POWWEB POWWEB – They host this site. And their data centres are wind powered! Click here for a super deal.
Tranzfers Tranzfers – For sending foreign exchange pretty much anywhere in the world. Cheaper than the banks with better rates. Sign up with this link!