Ralph Johnson and a group of students, colleages and friends meets once a week to discuss recent papers they have read, mostly on patterns or pattern related subjects. They meet in the Digital Computer Lab (1304 W. Springfield, Urbana), and often go out to lunch together beforehand.
Joseph Yoder in conjunction with Jeff Barcalow has kept a nice list of topics that we've discussed at: http://www-cat.ncsa.uiuc.edu/~yoder/papers/patterns/patterns-list.html