Wikis are used in mathematics education in a variety of ways . As with Wikipedia, mathematics related Wikis provide pages and links that describe many different branches of mathematics. Another common use is as a portal for distributing and collecting mathematics course materials . This article describes the authors’ use of course wikis for two different purposes in two undergraduate math courses. In Calculus-I, a wiki was utilized to share and present the outcome of an optimization problem that required small groups to collect information about student homes’ attic insulation status and eventually to compute the optimal amount of new insulation to add that maximizes heating savings. The second wiki was for a small seminar-style course on Mathematical Mysteries where students collected and posted the results of their research relating to famous unsolved problems in mathematics. This wiki was also used as a platform for in-class presentations by the students and the instructors. In both cases, the bulk of the wiki contribution was by students.