Going to get out of order a bit. WPS track this morning was great! And I was so sad to miss the WPS BOF yesterday.
52N was amazing with a open layers + graphical workflow layout browser app (that defines a new process that can be executed). Both GeoServer and 52N had running demos (which is always brave); ZooWPS went through the structure of their project and seem to be taking on more languages in the future.
The big news for me was the creation of a vendor neutral public email list via the OGC for WPS instances to collaborate. One of the results of the OGC WPS test bed I participated in this year was the lack sanity for a client application trying to connect and communicate with each. Indeed you are reduced to GeoJasn because GML requires 2 execution paths (one for schema and one for the data conforming to the schema).
I hope to set up a WPS dinner this evening; thus far GeoServer and 52N are represented; I need to hunt down Zoo project and others...