For more math oriented challenges (more project euler like), check out the monthly IBM 'I ponder this'. These are usually quite challenging, but the problems ar

For more math oriented challenges (more project euler like), check out the monthly IBM 'I ponder this'. These are usually quite challenging, but the problems are interesting and solutions are posted at the end of the month. http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/pages/index.html http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/pages/in...