Stuff I help run

Galaxy Zoo Forum
Galactic Orchids
Hackney Skeptics in the Pub
(Those are the obvious. See Alice's Projects for the rest)

The stuff I'm gladdest I've come across in life
Book: Daughter of Persia by Sattareh Farman Farmaian
Book: Reinventing Discovery by Michael Nielsen (PDF of chapter 1 here)
Talk: "Gin, Television and Social Surplus", also known as "Looking for the Mouse", by Clay Shirky (this used to be on his site, but it isn't now, for whatever reason) - video of talk
Essay: "A Mathematician's Lament" by Paul Lockhart

Galaxy Zoo, the Zooniverse, a few of the people, and related links

Galaxy Zoo: classify galaxies online
The Zooniverse (and all the other projects)
The Galaxy Zoo blog
Citizen Science Alliance
The Sloan Digital Survey
The Hubble Space Telescope
Chris Lintott's Universe
Beautiful Stars
W. C. Keel
Orbiting Frog

. . . and some zooite projects that came out of it:
Waveney's Irregular Galaxy Classifying Project
The Hyper-Velocity Stars Project

More astronomy links

Universe Today
Bad Astronomy
Portal to the Universe
Jonathan's Space Report
Sigma Orionis (Young Astronomers)
Solar System Dynamic Orrery
A Sky Full of Stars
Supernova Condensate
Space is Ace
Astronomers Without Borders
She is an Astronomer
The Scale of the Universe

Science, skepticism, friends, people with sense and humanity etc (these tend to overlap for some reason)

What is Skepticism?
What is Skepticism? - UK Skeptics
Jack of Kent
Science Digestive
Cardiff Skeptics (my old Skeptics in the Pub)
Rhys Morgan
Micro to tele
Economista Dentata
Science, Reason and Critical Thinking
Zeno's Blog
Reality Is My Religion
Dr Petra
Cubik's Rube
The Quackometer
Darryl Cunningham Investigates
David Colquhoun's Improbable Science
Don't Get Fooled Again
Purely a figment of your imagination
The 21st Floor
The 21st Floor's list of Skeptic speakers
Think Humanism
Friendly Atheist
Ten 23
Hayley is a Ghost
She Talks (Hayley's register of female speakers)
Answers in Genius
Butterflies and Wheels
A Latent Existence
Diary of a Benefit Scrounger
Benefit Scrounging Scum
(please note the above two are titled ironically - if this seems odd to you, please read them!)

Causes I support (No, I'm not listing every good cause on the planet. These are just some of my personal favourites.)

Science is Vital
Libel Reform
Sense About Science
Future's Vision and The Vision Library
Amnesty International
The Orchid Project
Freedom from Torture
World Parrot Trust

Smile Generators

Eric Idle's Galaxy Song with space pictures
Patrick Moore Plays the Xylophone
Astronomy Picture of the Day: Happy People Dancing on Planet Earth
Welcome to the Hotel Mauna Kea
Solar Beat
Overheard in Tuscaloosa: quotes from astrophysicists' metings
Mark Thomas
Questionable Content
Odd Fish
(The Customer Is) Not Always Right
Damn You Autocorrect
Hampsterdance (the original)
Mesmerizing blue ball factory
Honourable mention on Shelley the Republican