Fun sciency stuff

Optical illusions - Michael Bach's site with many fun and puzzling illusions

Project Implicit - test yourself for bias in a number of situations such as gender and race

Retraction Watch - what published material has been retracted or altered

Predatory journals - keep track of suspect journals and fraudulent material out there 

Gapminder - play around with statistical data in a simple way

Wordle - create you own word clouds

Existential comics - philosophical comics

In Swedish

Bioresurs - material för biologiundervisning

Matteboken.se - repetera dina mattekunskaper från årskurs 3 till universitetet