I hadn't ticked a checkbox that I really should have checked, and the two prompts I thought I had are -uh- not there.
It's all in working order now. To give me a prompt, all you have to do is click "Feed the Muse!" in the menu. You will then be able to create a New Topic with your prompt.
This is the only place that I allow anons to play like this, so I kind of expect a little responsibility on your behalf. That said, all prompts are welcome!