I actually had a site bookmarked for this very reason that provided some good, sound advice. I've always heard that a cougar (mountain lion) generally doesn't let you see it unless its considering attacking.

**100 yards away or more that is unattentive to you**

 - Avoid rapid movements, running, loud, excited talk.
 - Stay in groups; keep children with adults.

Probability of risk is slight, provided your response is appropriate.


**50 yards away with its ears up and attentive to you**

 - Hold small children; keep older children close to an adult.
 - Do not turn your back.
 - Look for sticks, rocks or other weapons and keep them at hand.
 - Watch the cat at all times.

Probability of attack is slight for adults given proper response.
Probability of attack is serious for unaccompanied children.


**Less than 50 yards away, staring intensely at you, or hiding;**

 - All of the above steps, plus place older children behind adults.
 - Seek a safer location, or one above the lion, if available.
 - Do not run.
 - Appear larger. Raise arms, objects, or jackets above your head.
 - Prepare to defend yourself.

Probability of attack is substantial.

**Intensely staring, crouching and/or creeping toward you**

 - Take all the above actions.
 - Moving slowly, position trees, boulders or other large objects between yourself and the lion.
 - Do not lose sight of the lion.
 - Smile! Show your teeth. (A woman attacked at Cuyamaca Rancho State Park may have saved herself by baring her teeth, growling and staring the lion down as it approached her).
 - Make loud, menacing sounds, like yelling and growling.
 - Throw things if the lion is close enough to hit.
 - Use lethal weapons if you have them.
 - Pepper spray may be effective if lion is downwind and close enough.

Probability of risk is serious if within 20 yards.

**Poised to attack**

 - Prepare to defend yourself in close combat
 - Fight back.
 - Make menacing noises.
 - Keep eye contact with the cat.
 - Act aggressively toward the 
 - Use a stick to charge the lion, thrusting the stick toward its face.
 - No stick? Yell loud and run toward the lion with arms high.
 - Stay beyond striking distance of its paws.

Source: [Link][1]


  [1]: http://www.angelfire.com/co/KlueLass/lions/ljohnson.html