I don't go to England much because they don't have many researchers in computational complexity, so I get a rare chance to talk to many of the researchers in this area. These workshops give us a chance for us to tell them about the latest in complexity and I can learn about areas I don't keep up with as much as I should.
Leslie Ann Goldberg gave a neat talk on the hardness of estimating the Tutte polynomial of graphs on a variety of points. I never really learned about the Tutte polynomial; it has some cool properties that for various parameters can count properties of graphs such as number of connected components. Goldberg and Mark Jerrum showed some of the approximations are #P-hard, that is hard for counting solutions of NP problems. We rarely see #P-hardness for approximating as all #P problems can be approximated probabilistically with an NP oracle. The Tutte polynomial is harder to approximate on some negative values because of the cancellations given by negative terms.