Any similar sites you'd suggest, besides Project Euler and TopCoder? I've worked through much of PythonChallenge, but I'm more interested in sites that aren't as closely tied to a specific language.
Programming Praxis (http://programmingpraxis.com) provides a collection of etudes, updated weekly, for the education and enjoyment of the savvy programer. Although there is some math content (the current exercise uses the chinese remainder theorem), Programming Praxis is much less math-oriented than Project Euler.
Do you know about Sphere Online Judge? (http://www.spoj.pl/) It supports a lot of languages. It still contains mostly algorithmic problems though, making it a superset of the kinds of problems at Project Euler but still a tiny subset of general programming.