Google release a fun little game that actually makes Google smarter.  A few intelligent individuals are trying to solve problems using humans rather then computers, one example of this is Mycroft Networks which breaks big problems down into little pieces so that they can be placed in banner ads to be solved by millions of web surfers.

Google Image Labeler decided to take all the fun of The $100,000 Pyramid game and turn that into image gathering intelligence.  Basically, you are paired up with another random person on the net for 1min 30sec.  You're then shown a series of photos which you must 'tag' (basically assigning keywords and descriptions of the image.)  You're doing this together with your partner in real time, except you can't see what they're typing.  If both of you select the same 'tag' congratulation, you now move onto the next photo in your 1:30 time alloment.  You're scored by how many photos you can burn through before the time is up. 

Why this works so well:

1. It's a game - it's fun, and it's addicting

2. It feeds your ego cause they display the top overall winners, and the best for today.

3.  It's super clever.  Basically it's very difficult to game the system to win, since you don't know who you're playing with.  It's even harder to tag the photo with incorrect data, cause the chances of your partner doing the same is nil.

4. It appears to be generating very intelligent tags.