I'm running a 4400 ficathon over at the newly revamped 4400abductees.com forum.
For those who do not know what a ficathon is here's a quick explanation. Each person in a ficathon puts in a request (or several - in this case 2) for a story, these can be as specific or as broad as they like, and are guaranteed one story will be written for them. In return they agree to write one story for someone else (minimum 800 words) and to meet the required deadline for hand in that signals the end of the ficathon. No one apart from the organiser knows who's writing whose requests until stories come in, so you get a - hopefully nice - surprise when the deadline is up; a fanfic specially written to your specifications.
The schedule:
Announcement for signups - 29th May
End of signup phase - 21st June
Assignments emailed out - 28th June
Decision period on assignments and asking for reassignments - 29th June until 12th July
One week reminder email - 23rd July
Deadline week of submission for fic - 1st August until 7th August.
More details here -
http://4400abductees.com/index.php?showtopic=600