• The design of the Inferno virtual machine: Phil Winterbottom and Rob Pike.
• Dis Virtual Machine Specification: by Vita Nuova Limited.
• Catalog of Free Compilers and Interpreters: This list catalogues freely available software for language tools, which includes the following: compilers, compiler generators, interpreters, translators, important libraries, assemblers, etc. -- things whose user interface is a language. Natural language processing tools may also be included.

OS research:

• NASM: A very good x86 assembler written in C. (Note: can be used with LCC)
• LCC: A retargetable compiler for ANSI C.
• IA-32 System Programming Guide: The most important documentation for the x86 (look for the 386 docs too) and by far the easiest to read.
• OSRC: Operating System Resource Center - A fairly good resource.
• OSD: Operating System's for Dunces
• John Fine's home page: Some good tools and tutorials.
• MMURTL: Good for the very green.
• GO! OS: General Componentization of the Operating System (component-based OS using passive objects)
• ATA-ATAPI.COM by Hale Landis: Very good source of information on ATA/ATAPI standards.  An example driver with full source is available for download (based on ATA-4).

And a little hardware:

• Microchip
• Xilinx
• OPENCORES.ORG
• The Burrow
• Emulation Technology, Inc.
• Needham's Device Programmers

Personal favorites:

• FlipCode: Daily game development news, and resources.
• GameDev: Game development news, forums, articles, and resources.
• Gibson Research Corporation: Security tools and a starting point for learning more about computer security.
• JLN Labs: A very interesting site featuring Electrohydrodynamic (EHD) devices that use a direct conversion of electrical energy into kinetic energy.
• Calculus Made Easy: In a world of TV and discrete equations, this book is perhaps the best book to read for learning or refreshing the skills of calculus.  Silvanus P. Thompson gives the subject levity by maintaining the readers attention with humor. You may be surprised to find that the book was originally written in 1910.  The art of calculus is far from the malediction of which most fools consider it being.  What one fool can do, another can.  (In case the fools at Amazon move the link, here's the ISBN: 0312185480).
• Complex Numbers: For those of you who need a start point for Quaternions, this is a good site to start with.
• Plücker Coordinates: A lighter geometric explanation with cool graphics.
• Euclid's Elements: Personally, I believe it's an interesting read and a good logic exercise for the brain.  Sadly, for the most part, people don't read old stuff like this anymore.
• UWB: Ultra-Wide Band Working Group.  Some interesting devices will certainly evolve from this technology.  I'm
• GLScene: An open source project set out to create a very powerful set of Delphi components that encapsulate the OpenGL API.  The project was originally started a few years ago by my good friend Mike Lischke.  If you think GLScene is cool, then you should go to Mike's site as well!