I didn't see this mentioned elsewhere in the forums, so thought I would mention it.
I think this is cool.

Google added some graphing functionality to its main search page. Here is the link from the Google blog introducing this feature:

"Showing some love to math lovers"
insidesearch.blogspot.com/2011/12/showing-some-love-to-math-lovers.html

It also includes some sample curves, so users get an idea how to use this feature.

Enjoy.