The uses for the Flickr API never cease to amaze me. One of them that I've been playing with for the past week is Phrasr, a service that takes several words you throw at it and spits them back out as photos from Flickr.
You can individually change each photo to better suite the word. I found it to be pretty off the mark on most words, but spot on for others. Half the fun is exploring additional photos to get a better match.
When you're done selecting your photos you can then publish the phrase to everyone else. It goes in a public pool, and actually viewing the shot plays like a photo slide show, and clicking any of the shots takes you right to the photo page on Flickr.
Is it useful? Not really, but it's certainly fun, and would be great to mash up with Twitter.