52 Sci-fi and Fantasy writing prompts.
In case the muse fails you, here is a link to someone who has graciously given us a prompt a week based on her favorite books.
I like in particular:
Week 2: Write a page of dialogue between a dying but powerful dragon and
the boy who stumbled into his lair in search of something with which to
save his people. (Inspired by The Riftwar Saga)
Week 19: Write a chase scene around an old castle and its grounds
between a young witch on a broom and an angry dragon. (Inspired by Harry Potter and the Goblet of Fire)
Week 23: Write a resourceful fight scene on a bridge between an army of
animated broken umbrellas and a zombielike brigade of men wielding smog
over a book. (Inspired by Un Lun Dun)
Now you have no excuses.