Get your app to a "feature complete" state. That is, all the features you intend to include in the final product should be functioning.
Bring at least one device per team to class on May 26, with your app installed. We will spend class time doing a very simple and powerful kind of user testing. Roughly: "Watch other people use your software while keeping your mouth shut. Also, try not to cry."
The following week will involve debugging and polishing.