Google Product Manager here. I get on the bus about 8:30 and start working. In Mountain View (where meetings commence) by 10a. Usually pretty solid w/ meetings from 10-4. Get on a 4 or 4:30 bus and work again (email, etc) until I get off at 5:30 or 6.

Probably 2-3 days a week I put in an hour (or two, rarely 3) after the kids are in bed.