No Snape tonight. I'm hot, I'm tired, and Snape takes brains. (That's not a plotbunny, but if someone wants to stretch it into one, far be it from me to complain.)Makes me wish I'd ever watched Buffy, Stargate or Smallville.
Crossovers, 'cos those are what comes easiest to me.
Firefly/Dr.Who, Martha/Inara, The Doctor/Simon. (Doctor-doctor, companion-companion): The Tardis materializes in Serenity. Due to some energy glitch, it can't just skip away. Mal's crew is in the middle of some quasi-legal activity, which they decide to involve the Doctor in since his timeship landed on their nifty lockpicking software. So the Doctor winds up helping them break into somewhere. In the meantime, Inara has a long talk with Martha about the annoyance of being attracted to someone who's too caught up in his work to pay attention to her... they comfort each other. River has Interesting Things to say about the Doctor, and goes into screaming fits--Doc and Simon both help her get settled (i.e. drugged into unconsciousness), and then the two of them are alone, together... sparks fly.
Ninth Gate/Hannibal series, Corso/Hannibal Lector: Post-Silence, Dr. Lector spends a lot of time in intellectual circuits, but specifically avoiding his previous specialty. He attends a lot of lectures at universities. Corso attends some as well, researching clients; they meet at a talk about authenticating 18th-century wills. Corso admits to having a few pieces in his collection; Hannibal is curious. (MY ETCHINGS, LET ME SHOW YOU THEM.) They go back to Corso's place and actually look at a couple examples of classic literature (Hannibal's fascinated by the explanations of who-gets-what-and-why; Corso just cares about tracking the book collection mentioned therein.) before falling madly in bed together and have dirty, aggressive, spiteful, one-shot sex, after which both hope they'll never see each other again.