The Guilded Rose Kata fictionalizes the experience of working with someone else's code. You'll probably groan when you first see the code provided to you. The amount of code isn't overwhelming, its the prefect balance to evoke the feeling, "I can't wait to re-write this cruft." It's suggested that you use Test Driven Development with this kata. Once done, read the **spoiler** section at http://craftsmanship.sv.cmu.edu/katas/gilded-rose-kata to see if you had a similar experience or not.
The above link also provides versions of the kata in C#, Ruby and Java. Google provides other implementation in other languages too.
So, bring yourselves, your colleagues and your favorite IDE along and we'll have some pain/fun (delete as appropriate).