Here are a bunch of websites I like:

• My wife’s website with lots of great photography and trip reports: http://www.13ergirl.com
• PETSc, the portable extensible toolkit for scientific computing: http://www.mcs.anl.gov/petsc/
• Matt’s interactive C++ compiler: http://gcc.godbolt.org/
• The intel intrinsics guide: https://software.intel.com/sites/landingpage/IntrinsicsGuide/#
• Github: https://github.com/