Okay, I've just finished watching the Firefly DVDs with my mother, and the urge to write a Serenity fanfic is almost irresistable.
Here's what I've got for plot ideas so far.
On the way back to Paquin to return Inara to the school, Serenity is attacked by thugs trying to retrieve River on a Parliament bounty, however River's new skills are more than a match for them. Inara convinces Mal that taking her back is too risky, that they can't go anywhere that they'd be expected. So, they set course for Boros, where anti-Alliance feeling is running high after the broadcast.
On Boros, Mal runs into someone who wants to nominate him as Vice-President of the new Independent government that's being formed, and the very idea of becoming a politician scares him badly.
Inara finds out that she's been declared dead at the guild, and has to go to one of Boros' moons, Ares, to prove herself to someone she knew back on Sihnohn. Mal volunteers to go with her, and the shuttle is shot down on Ares, forcing them to work together to stay alive.
River, Simon, and Kaylee meet the leader of the group who helped Simon break River out of the academy, and find out that he's looking for a group of later escapees who weren't able to make their rendezvous and disappeared. River insists on helping with the search. A young anti-alliance contact working with them tries to sweep Kaylee off her feet, leaving Simon not quite sure how to react to someone else paying attention to her.
Meanwhile, Jayne finds out about an alliance sympathizer who escaped with key components/schematics to the Boros power system and is hiding up in the mountains. Jayne convinces Zoe to go with him to catch the guy and bring the stuff back for a reward... he's excited about spending more time with Zoe, but didn't expect a revelation about something that Zoe still has to remember Wash by...
I'll be posting on 'other shows fanfic' once I start it.