Google's home page has a hidden surprise - place your mouse cursor over the "Im Feeling Lucky" button and it will go for a spin.
Here is a video:
Depending on which one you click on, Google will take you to a specific type of search or a specific Google service.
Alex documented and Jerome where they go, including:
- I'm Feeling Doodly: random doodle
- I'm Feeling Playful: random interactive doodle
- I'm Feeling Artistic: random Google Art Project
- I'm Feeling Hungry: search for restaurants
- I'm Feeling Puzzled: random A Google A Day question
- I'm Feeling Trendy: Google Hot Trends
- I'm Feeling Stellar: image search for [orion+nebula]
- I'm Feeling Wonderful: random World Wonder Project
Forum discussion at Google+.

Comments:
Praveen Sharma
08/14/2012 12:57 pm
Have you tried it Barry? I can't see it.
Barry Schwartz
08/14/2012 12:58 pm
Yes, I tried it. I made the video.
Praveen Sharma
08/14/2012 01:03 pm
I think its not working with Google Instant ON.
Barry Schwartz
08/14/2012 01:04 pm
Yes it is.
Jeffrey Purdon
08/14/2012 04:02 pm
As far as I can tell, this is only happening in Chrome (maybe Safari, I don't have it installed to check).
Brandon
08/27/2012 08:30 pm
Seems to not be working anymore.