We have been using COGENT to introduce students to practical issues related to cognitive modelling for the past two years. In this talk I'll introduce briefly the background of the course and students (what they know in advance, and what we try to teach them!) before introducing some models created by students in the course of their practical assignments. The models take two forms: firstly, there are the students' creative models of multi-column addition, and secondly there are re-implementations done by them of other people's work. Having shown what students can do with COGENT, I'll try to evaluate its use in a teaching environment.