The intelligent features that creep into Google search unannouned amaze me. The calculator function is old hat. I use it a fair bit out of laziness. My homepage is Google Desktop so it’s usually quicker for me to get to Google than to calc.exe. That in itself is saying something.
My son wanted to know how old Stephen Hawking is as he’s reading one of his books. I went onto Google and typed How old is Stephen Hawking more out of curiosity than anything else. I wanted to see how they’d handle my search, being in lay english as opposed to a keyword search. The result amazed me:

Google returned a first result (under book matches) that gave simply his birthdate, followed by the source (wikipedia)
I tried a few more to see how it would do. First result was similar for Larry Page (also Wikipedia), Second result for Sergey Brin gave me his age but not date of birth. Bill Gates, Steve Ballmer, Steve Jobs all get a first result from wikipedia with their birthdate. For some reason, Woz does not, but the fourth serp does give a direct indication in the teaser.
Sadly, they failed when I tried to find out how old Frank Arrigo is, but the internet movie database made up for that with interesting stuff about a lesser Frank Arrigo ;o) I’m also an ageless piece of dust in Google’s eyes but I was very happy to see that out of the millions of Mark Cohen’s in the world, if you search for How old is Mark Cohen on Google, they assume the one you’re most likely to want to know about is me