I love the multiverse5000. I love space shows, books, and movies, and I love crossovers. The Multiverse challenge is a crossover ficathon for space shows! So, like Star Wars/Star Trek and Firefly/Doctor Who and BSG/B5 and Honor Harrington/Miles Vorkosigan and anything else you can think of. It is really, really awesome, and you should all go and participate either by leaving prompts or writing fic or both. It's being run using the new prompting feature on AO3. Rules post is here.