Codility tech team is from Warsaw University, we are more than familiar with TopCoder, ACM CPC, IOI etc. We deliberately keep Codility tasks at fundamental level. Codility is not a competition for 100 world's best programmers, it is a tool to tell decent programmers from poor ones. We can raise the bar arbitrarily high, if there is a customer who needs it.

Thanks for the tip, topcoder looks pretty interesting in general, too.

Also Project Euler might be worth a look. It focusses on solving math-related problems with progams.