A jokester's definition of insomnia: When you keep a bunch of innocent sheep jumping over a fence all night just because you can't get to sleep.

Experts agree that the time-honored practice of counting sheep or doing another such monotonous task may help induce sleep. Sleep specialists provide these additional tips to help you reach dreamland.

Avoid caffeine (including caffeine-containing drugs), nicotine, and alcohol for four to six hours before bedtime. The first two are stimulants that can make it difficult to sleep. And while alcohol may have a sedating effect at first, it tends to disturb sleep after several hours.

Don't exercise within four to six hours of bedtime. Working out earlier in the day, though, not only doesn't hinder sleep, but can actually improve it.

Perform relaxing rituals before bed, such as taking a warm bath, listening to relaxing music, or eating a light snack.

Before going to bed, try as much as possible to put your worries out of your mind and plan to address them another time.

Reserve your bed for sleeping. To preserve the association between bed and slumber, don't watch television or do work in bed.

Go to bed only when sleepy. If you can't fall asleep within 15 to 20 minutes, get out of bed and read a book or do another relaxing activity for awhile, rather than trying harder to fall asleep.

Make sure your bed is comfortable and the bedroom is conducive to restful sleep -- quiet and at a comfortable temperature, for example.

Wake up about the same time every day, even on weekends, to normalize the sleep-wake schedule.

Don't take naps, or nap during the mid-afternoon for no more than 30 minutes.