I recently received an e-mail concerning the following free resource: http://mathhistoryproblems.wwu.edu/problem_select.asp. From the e-mail:

[This] is a data base of more than 1600 historical problems connected with mathematical topics, skills, and concepts taught in secondary schools and colleges. The problems are categorized within broad areas of number, algebra, geometry, measurement, trigonometry, number theory, probability, statistics, pre-calculus, calculus, logic, discrete mathematics, and recreational mathematics. Revealing international contributions and changing cultures, the problems span the full history of mathematics (2000 B.C. – 1940). Each problem statement includes its source and solution commentary.