Stoplight Clock to keep the kids in bed
I have a friend who posted on a social networking service that, as most kids do, his daughter will awaken and get out bed before she should...until he purchased a particular clock.
It's the Stoplight Sleep Enhancing Clock.
"...toddlers know their colors and understand that red means stop and green means go...When the red light is on, kids will understand that it is still time to sleep. When the green light turns on, kids will know that it is time to get out of bed. A digital clock and optional beeping alarm function are also included as well as a nightlight feature that can be used separately."
To keep time constant in the clock due to a power outage, it needs two AA batteries (which are not included).