PhotoWord is a unique and incredibly addictive game (in a good way).
Its best described as a photo guessing game. You see 6 photos that have a common tag, and then you choose the tag from one of the buttons. (See the screenshot.)
You can play easy (2 buttons), medium (4 buttons), or hard (6 buttons). Easy is really, really easy, and hard is pretty darn hard. There are over a quintillion combinations of buttons (all but one has a random word), and over 100,000 possible images.
Photographers sometimes tag their photos in strange ways (e.g., an ocean wave that reminds them of "baseball"), but thats part of the fun!
Each correct guess is worth 5 points, and theres a penalty for wrong answers. A game is 20 sets of photos, or 100 possible points.
You dont need a Flickr account to play, nor do you sign in if you do have one. You do have to be online to play.
(This product uses the Flickr API but is not endorsed or certified by Flickr.)