Headaches come in many different varieties. There's the all-time classic tension headache (think vanilla), so common that just about anyone who's got a head has experienced one. Eyestrain, fatigue, and stress (mental or emotional) are all key ingredients in this flavor.

Next on the list is the sinus headache. It often comes on during or after nasal congestion or a runny nose. Pain is usually felt at the front of the head. It is commonly worse in cold, damp weather and in mornings; it lessens in afternoons.

Then there's the cluster headache, which, just as the name implies, typically occurs in "clusters" ranging from two attacks a week to several a day. Episodes usually last for six to eight weeks or sometimes longer. Unlike with tension headaches, stress isn't a triggering factor. For some unknown reason, they affect more men than women.

Ice-pick headaches are fairly rare - but when they strike, watch out! Severe pain is localized to one small spot and comes without warning, like you've just been hit over the head with an ice pick. The medical name for ice-pick headache is chronic paroxysmal hemicrania. Attacks usually last less than an hour - generally 10 to 15 minutes.

Finally, we have the migraine - no ordinary headache. Pain ranges from mild to severe and isn't necessarily the only symptom. Migraines can also trigger nausea and vomiting. In some people with migraines, visual disturbances called "auras" (like seeing zigzag flashes and shimmering lights) may show up for about 10 to 30 minutes right before the migraine starts. A migraine "attack" can last from two to 72 hours. The agony usually stops people in their tracks. It disrupts work and play activities, and many sufferers need to retreat and rest until the migraine is over.

Rarely, certain headaches can be a sign of a serious problem. For example, headaches that appear out of the blue with fever and a stiff neck could point to a brain infection called meningitis. Headaches plus signs of imbalance and double vision can be a warning of a stroke.

The take-home message: Headaches are a pain, but they usually disappear on their own. But if your headaches are severe and long-lasting, see your doctor immediately - so you can put your mind at rest.