The benefits of active learning on student performance are well documented. However, in large mathematics classes with active learning components, one challenge is making the most effective use of the limited time any one student may interact with the instructor. I discuss the role educational technology can play in shaping the active learning environment, directing students and helping them gauge their mastery of course concepts and skills. In the first part of the talk, I'll describe our initial progress in developing classroom educational technologies and employing them in math classes at the University of Minnesota. In the second part, I will describe open challenges for future development of the technology, focusing on answer validation and giving students appropriate feedback and credit for their responses.