We're talking about kitchens this month, but kitchen timers can be used in and out of the kitchen. A timer is a great motivator for getting things done. It's also great if you've got a little chef or someone learning to tell time.
Design Sponge shared a plentiful roundup of timers a while back. It's pretty comprehensive!
We've blogged before about the Time Timer which is often used in Montessori-style classrooms.
We got our timer from Anthropologie a month or so ago for about 12 bucks and are quite happy with it. It's the same one as the yellow ones in the first picture above.