Powered by the BBC
The BBC is the latest online entity to create APIs and allow anyone to make use of their content in interesting ways. It's only in beta at the moment, but it looks interesting.
There are a few prototype systems which look like they could be useful. If anyone fancies knocking up a service to check the BBC film release calendar and email users when a new film directed/produced/starring someone they have designated on a watch list, I'd use it.