Does anyone know how I got this rainbow?

http://i.imgur.com/vwZPN.png

What is the url of the rainbow image?

Nyan cat?

George: I forgot to check the its URL, and I couldn't reproduce it, sorry.

I first thought it was a bug with the Les Paul doodle or something related to my query (cf. http://blogoscoped.com/archive/2008-06-17-n27.html). I have no idea what it is.

I think it is the colors of a flag for the gay and lesbian movement.
http://en.wikipedia.org/wiki/Rainbow_flag_(LGBT_movement)

Apparently June 2010 was lesbian, gay, bisexual, and transgender pride month. Perhaps it is again this year.
http://www.whitehouse.gov/the-press-office/presidential-proclamation-lesbian-gay-bisexual-and-transgender-pride-month

I got it too.. and grabbed the code from the page:

http://www.linux-forums.net/threads/weird-google-rainbow-search-button.2679/

George R Yes it looks like it. Google did this before.

WebSonic.nl So which keywords would return this easter egg?

Well, in the past it was Gay, Lesbian, etc. Not working now though.