I work for Google, and I've asked for -- and been granted -- IP for a side project I've been working on. Actually under California state law I probably had rights to the IP anyway (I haven't worked on it at work or with work resources) but I've been officially granted a legal promise that Google won't sue me into bankruptcy to try and assert ownership. :)

It wasn't a hard thing to do, and I get the impression that unless you're planning on directly competing with something they care about, they're pretty liberal with such releases.