Mathematical
- The CTRC category theory seminar in Montreal.
- MathOverflow and StackExchange are mathematics forums.
- The unapologetic mathematician is a blath (a blog about math).
- The famous n-category cafe, yet another blath.
- Prakash Panangaden and Robert Seely are mentors and colleagues.
- This interactive julia set is pretty cool.
- This prime number ticker is a neat number theory visualization.
Pedagogical
- Kids of the future will learn algebra by playing Dragonbox.
- A charming introduction to the world of the infinite.
- Did you know Google can be used as a calculator and function grapher?
- Cornell has published a set of very nice conceptual calculus questions.
- This youtube channel is chalk full of worked out calculus problems.
- Touch trigonometry: how does each coloured line give the value of a trig function?
- More or less is a BBC podcast on stats.
- Find the error is a short online set of interesting calculus problems.
- Gilbert Strang's fantastic linear algebra lectures from MIT.
- Scans of Oliver Byrne's 1847 colour edition of Euclid's Elements.
Internetical
- Everyone should know about concerts a emporter.
- Said the gramophone, a friend's music blog.
- The datagenetics blog is fun for nerds.
- The big picture reports on current world news stories photographically.
- Without a doubt, the best radio show known to me is NPR's this american life.
- Sports club stats will provide hours of fun for hockey nerds.
- The IMSLP is an online collection of free sheet music.