What is a pop quiz? Are they done at any UK universities?

A pop quiz is a surprise test to make sure you've been studying and understand the work . They are done in the US in elementary school and high school, not just university, and I have seen them done in UK high schools as well but they aren't called pop quizzes here. They may be done at uni but I don't think most universities would give them.

Haha, yeah they are just random quizzes that teachers give you.

Their idea is that you've been paying attention in class, and done all the homework so you should be able to do well on a test without any prior knowledge of that test.

And yeah, the UK does them they just call them something else.

They're quizzes which teachers give to students without telling them beforehand, testing that they've been doing their work and paying attention. They're not necessarily in lectures, and are done from elementary school on