It varies a great deal. Each team has a distinctive culture, and there's a lot of individual variation too.
I typically arrive at Google about 9:20 (until recently the breakfast cafeteria at the NYC office closed at 9:30, although that's no longer the case I've kept the habit), but don't really start working until ~10. If I have plans in the evening I'll leave around 6, if not, I'll stay for dinner and keep working until 8-8:30. I've never come in on the weekend.
One coworker on my team is always there before I arrive, and is always still there when I leave, but everyone else on my team floats in gradually until 11:30 (when we have our daily standup), and leaves sometime between 7 and 10.
While some days I may spend 10 hours in the office building, consider that this includes 3 meals and usually at least one other major distraction (a tech talk, a break in the game room, TGIF, or something).
Edit: I've been in the NYC office around 4 months.
Another Aussie Googler in the NYC office? Drop me a line (see my profile).
Personally my schedule varies. Lately I've been getting in between 11 and 1 and staying until dinner (6:30) or later, sometimes very late (midnight+). Not all of that is work time as I often end up hanging out with other night owls.
My team is generally on a more normal schedule. Nearly everyone in the group is gone at or by dinner.
I typically arrive at Google about 9:20 (until recently the breakfast cafeteria at the NYC office closed at 9:30, although that's no longer the case I've kept the habit), but don't really start working until ~10. If I have plans in the evening I'll leave around 6, if not, I'll stay for dinner and keep working until 8-8:30. I've never come in on the weekend.
One coworker on my team is always there before I arrive, and is always still there when I leave, but everyone else on my team floats in gradually until 11:30 (when we have our daily standup), and leaves sometime between 7 and 10.
While some days I may spend 10 hours in the office building, consider that this includes 3 meals and usually at least one other major distraction (a tech talk, a break in the game room, TGIF, or something).
Edit: I've been in the NYC office around 4 months.