OTP is fun because every four months they run a contest that invites you to write a piece of fiction on a very specific theme. It is free to enter and the first place winner gets 180 USD. They don't place any limits on genre: anything goes, from literary fiction to pulp to high concept sci fi or whatever.
Mini contests are super tiny, but still come with a $15 prize for the winner. If you're like me and you're looking for a quick way to boost your writerly self-esteem by submitting some work, this could be it. The current contest has a 25-word limit (and yes, the theme is something you can reasonably complete in 25 words). Deadline is April 28, 2013.
To get the theme for the mini contest, you have to subscribe to the newsletter, which is infrequent and succinct and purple toned (just in case the colour of the newsletter has any bearing on your desire to receive it). OTP uses the newsletter not only to let subscribers know about what's going on with the magazine and contests but also to brag about writers who have been part of their contests and who have gone on to find success elsewhere. They also recommend stories published in other venues, just because they love stories. I think that's sweet.
(I won't say what the current theme is because I think you should just get the newsletter if you're interested, but let's say it's really ripe if you're into horror, suspense, or creepy stuff.)