If you've started reading Pinder (as you should be doing!) you'll notice how much of the history and the current politics of the EU revolve around different treaties and debates about how to expand or change treaties (or even forge new ones). The EU is, at its core, a rule-based institution grounded in a series of treaties that all of the member states have ratified. The current economic and fiscal crisis in Europe has once again brought the EU treaties into the spotlight, namely though the persistent question of whether adequate reforms for "economic governance" (a key term in EU parlance) in the Union can be made within the current treaty framework, or whether a new treaty is needed.
Here is a recent news article from EU Observer that will help bring you up to speed on this debate, which will certainly be something that folks in EU politics/policy circles will be discussing once you get to Brussels: http://euobserver.com/institutional/120053
What kind of institutional and political dynamics strike you as important as you read this article and read about the economic and fiscal crisis more generally? Where does authority lay on these types of questions in the EU?