I've been working on what I think is an interesting mashup of Stack-Exchange-provided data from the data dumps with another data source. Where should I announce it when I'm ready for people to try it out?
Edit: A deleted answer helpfully pointed out stackapps.com, but the tour page says:
Lots of topics are fair game, as long as they are about the Stack Exchange API, applications that use the Stack Exchange API, or scripts that work on the Stack Exchange network of websites.
It looks like you can promote an application in a question there, but I'm not that refers to apps that only use the static data dump and not the API.