Ross Street is probably the leading mathematician in the field of n-categories; he teaches at Macquarie University in Sydney, Australia. On July 11-16 2005 there was a conference at Macquarie in honor of his 60th birthday. Technically this conference was called Categorical Methods in Algebra, Geometry and Mathematical Physics, but in practice everyone called it the Streetfest. The party continued during July 18-26 at Australian National University down in Canberra: there was a workshop on the same subject, also in honor of Street's birthday. Over this two week period there was a total of 61 talks on a vast range of subjects, from string theory to number theory, all touching on categories in one way or another.
For now, you can see some photos of this conference here. I'll improve this page someday.