The Darwin Award post below reminds me of a joke I heard a while back. Seems that the Yellowstone Park Service made up a handout for hikers in the park that went a little something like this:
Advisory to Hikers
Yellowstone National Park is home to a wide variety of wildlife, some of which can be dangerous to hikers. Yellowstone has a significant population of two species of bear: the American Black Bear (Ursus americanus) and the Grizzly (Ursus arctos horribilis). Normally these bears will avoid people, but there are several practices the Park Service recommends to hikers to reduce the chance and the severity of an encounter.
STAY ON THE TRAILS - Bears tend to avoid the marked trail areas.
SCENT Bears are attracted to scent, so:
1) Dispose of all foodstuffs and wrappings in airtight containers, and preferably dispose of them in the Park provided bear-proof trash recepticles. If in primitive camping areas, burn or bury the materials rather than carry them on your person.
2) Refrain from wearing perfume or cologne when on the trail, and don't chew gum.
An encounter with a bear may result in an attack if the bear is startled or if young cubs are present. To reduce the possibility of surprising a bear, the park recommends attaching small bells to your boot laces. The unnatural noise of the bells may alert bears (which have an acute sense of hearing) that you are in the area, and they should avoid you.
DEFENSE IN CASE OF ATTACK
The National Park Service prohibits visitors from carrying firearms for self-protection. If attack seems imminent, the use of oleoresin capsicum sprays (pepper sprays) can be effective.
Do not run. Bears are much faster than humans and they can run you down.
Do not attempt to climb a tree. Bears climb better than humans as well, and can be quite tall when standing upright.
DROP TO THE GROUND AND PLAY DEAD - it is your best chance to avoid serious injury or death. If you do not appear to be a threat, the bear may leave you alone.
If, while hiking, you come across bear spoor it may be helpful if you can identify what type of bear is in your vicinity. Using a stick or similar instrument, break up the spoor and identify the contents. Black bear spoor may contain partially digested berries, insect parts, and vegitation. Grizzly bear spoor may contain small bells and smell like pepper.