This is a list of locations I find interesting.

  1. General science links
  2. Physics
  3. Mathematics
    • Paul Bourke has a great deal of resources. Those regarding geometry I found really helpful
  4. Resources for programmers.
    1. General programming
    2. Assembly
      • MASM forum is where I've learned a great deal about assembly
      • Flat Assembler is a great tool, especially that it's open source and free
      • Bogdan Ontanu is writing an assembler and an OS. See screenshots and download.
  5. Resources for surveyors
      1. Pedro Maciá García  has done a great job with LandDTM, enabling the surveyor to do a lot of interesting stuff. 
  6. Others
You may find it... interesting.