Mathematical Games suitable for undergraduates I am looking for mathematical games for an undergraduate `maths club' for interested students. I am thinking of things like topological tic-tac-toe and singularity chess. I have some funding for this so it would be nice if some of these games were available to purchase, although I am open to making the equipment myself if necessary.
So the question is: what are some more examples of games that should be of interest to undergraduates in maths?

Group twenty questions. Depending on the allowable class of groups the difficulty can be scaled.
