Bren's advice is very good. The Virtual Families game design (day/night) was in response to the many requests for day and night in our games. One of the natural results of that design is that the peeps will tend to do different things, and display different energy levels, according to the time of day. In the same way that 'real' people don't stay up and remain very active 24 hours a day, the peeps in Virtual Families respond in different ways to different times of the day, too. This is very different from Virtual Villagers and requires a different game play strategy, since the VF peeps need a good night's sleep.

If you can only play in the evening or at night, you should consider using the option to switch day and night or even do as several people have done, which is to set up several different player slots with reversed day/night cycles. That way, you can play the 'daytime' families while the 'nighttime' families are getting rest. And you never lack for wide-awake peeps to play with.