Their interpretation (and I got this directly from HR/Legal) was that any app, for any kind of 'smartphone', even if it was on your own time on all your own gear. They claimed that Google was in the business of 'smartphone applications' and so anything you wrote belonged to them. Even in California. I asked them if I wrote a kitchen timer application for the iPhone would they claim ownership, they answered in the affirmative.
And I did consult an attorney on that and his comments were that you could probably litigate it and win, although you would wouldn't be working there any more. So if you really wanted to write an app, just quit and write it, so much simpler legally, and you could keep all the profits rather than run the risk of losing all the profit and ownership to Google.
Does this refer to apps written on company time or using company resources? Or any application written for a phone from anywhere at any time?