i just came out of the StreamInsight lecture at the PDC.
StreamInsight is new coming framework for handling the very common scenario
of pub/sub for durable events.
it is owned by the SQL Server team but they built it in as a modular component that
can run without any dependency of existence SQL Server (i.e. it can run in memory
without additional installation).
it is still in it Beta 2 stage but it seem very promising.