Oh, yeah, I have at least 20 fic ideas in my WIP folder... just haven't been able to get enough traction on any of them to get past the idea phase.

The nice thing about the ficathon is that you can use WIPs - so if you have something you're already working on, you could use that, as long as 15,000 of the words are new (i.e. never been posted before the ficathon).