We attended FOSS4G this year in Denver, Colorado. Friday was a PostGIS bonanza with 5 PostGIS talks back to back including ours.
The crowd was huge. All the PostGIS talks as I recall were so packed that there were not enough seats to accommodate everyone. A more comprehensive
detail of the events is described on OpenGeo FOSS4G Day #5
We admit to overstuffing our slides with SQL and ran short on time at the end. Leo complained and vowed to do a better job next time.
We really weren't expecting such a large crowd. Admittedly I'm all for the after conference experience which is much longer than the conference which is why I tend to make slides that are very dense. WARNING: The following slides feature SQL doing unconventional things suitable only for mature audiences. Viewer discretion is adviced.. You can check out our slides here PostGIS 2.0 the new stuff.