Just crossed off my to-do list: write abstract for Beer and Algorithms talk on Monday.
"Category theory: the least you need to know"
The purpose of category theory is to define the relationships between objects in a category of related objects. This worthy but extremely vague goal turns out to have applications all over CS, particularly in areas such as programming language design, concurrency, and information integration. We'll introduce a few basic concepts of category theory -- just enough so that when the person who sits next to you starts talking about functors and morphisms, you won't be entirely lost -- and discuss how category theory is being applied to solve real problems.
Next, to do by Monday: understand anything at all about category theory.