I just found this gem from /r/Programming.
Top Coder Algorithm Tutorials
I’ve only gone through a couple of the tutorials yet but they all look like interesting reads. Not all the tutorials are about algorithms, they tutorials on other programming topics like data structures and regular expression. If you’re interesting in learning about programming in general then you should check it out.
I found this link from a blog post by Bill the Lizard.
Bill lists out a lot of good sites that host puzzles to solve. Far warning, you might want to say away from Project Euler. They have some nasty challenges.
You also might want to check out this SO question. It’s where I found Bill’s blog and was the link posted on reddit.