Here are some links to organisations or projects that I think are fantastic (in no particular order):

Science:

CERN: http://cern.ch

ATLAS: http://atlas.web.cern.ch

LAL: http://www.lal.in2p3.fr

My home institute.

Manchester HEP: http://www.hep.man.ac.uk

The institute I did my PhD with.

Working with women in STEM (Science, Technology, Engineering and Mathematics):

ScienceGrrl: http://sciencegrrl.co.uk

Stemettes: http://stemettes.org

For while the code is compiling:

PHD Comics: http://phdcomics.com/comics.php

xkcd: http://xkcd.com

Blogs I read:

The Spectrum Of Riemannium: thespectrumofriemannium.com