I'm a little disappointed there have been no responses. It means that either (1) there are no blog carnivals anyone knows about; (2) people don't know what blog carnivals are; or (3) people don't care to share info, only to pimp their own blogs.
To answer (2), a blog carnival is when a bunch of bloggers post about the same subject, and all the posts get compiled in one place. This creates some decent linkjuice on its own, gets the blogs some great exposure, and if there's cross-linking involved, can really help your PR and Alexa rankings. Plus, you'll find like-minded bloggers whom you can build a relationship with.
Is there anyone out there interested in something like this? If we can get a few people to commit, I'll be happy to host it.