From time to time I get migraines. Most people know them as a severe headache that's sensitive to light and sound, but they can have a whole host of strange symptoms as well. My migraines do not hurt very much, thankfully, but they can get weird sometimes. Here is a non-exhaustive list of things that can happen while I have a migraine; I only get a few of these at once.

• Alteration of mood, in particular irritability. This is often the first symptom I get. I may suddenly get very annoyed at somebody out of proportion with their conduct. If I don't notice the feeling, I may snap or quip at them. Since I almost never engage in verbal violence, this is a high-accuracy indicator of an incoming migraine. Later in the migraine I sometimes get mild waves of depression and euphoria. I get feelings of numinosity or significance more commonly during migraines than not. Random objects or sounds can seem important or creepy.
• My most common visual symptom is seeing small miscolored, blurred, or blind spots. These last between a few seconds and a few minutes. I don't think I notice any of the "fortification hallucinations" common in other migraineurs. (EDIT 2014-06-26: This may not be a migraine symptom after all. I'm still gathering information on this.)
• I do sometimes get a sensitivity to light. Usually only sunlight is bright enough to hurt, but occasionally less bright lights are uncomfortable. Along with this, sometimes my perception of environmental lighting changes a little. Bright things get brighter and dark things get darker, and in general colors appear more vivid. This sometimes makes the world around me appear abnormally beautiful, and is sometimes associated with mild euphoria.
• Sometimes my ability to recognize objects by sight gets slowed down quite a bit. Have you ever had an experience where you see an odd-shaped object in your field of vision and can't figure out what it is for a while? This can happen much more frequently while I have a migraine. When a new object enters my visual field it may take me a second or two to recognize it visually. Usually I don't mind this, but it can be inconvenient sometimes. Under normal circumstances I enjoy taking late-night walks in the dark, but sometimes during a migraine, every other plant or rock I cross in the dark will appear threatening until I take a good look at it, turning the night walk from a relaxing contemplative event into a horror show.
• I wrote earlier about the mild hypnagogic hallucinations I sometimes get when my eyes are closed and I'm approaching sleep. Usually the images I see are very dim, barely brighter than the snowy eigengrau from which they originate. Sometimes when I have a migraine, these hallucinations can become much more vivid, involving all manner of interesting colors and flowing shapes. The images don't have any emotional content; I just see them, and sometimes they're mildly amusing.
• Moving on to audio symptoms, I can sometimes be extra sensitive to loud sounds and music. Normally my maximal tolerable volume for loud sounds is a little bit below the threshold for potential hearing damage (most people tolerate sounds much louder than that). During a migraine, my maximum comfortable volume can be somewhat lower.
• More commonly, I'll have an emotional intolerance to sounds. This one is hard to describe. Sometimes when I have a migraine, some sounds will make me very annoyed or angry. The volume of the sound is not as important as the quality of the sound. In general, uninvited human-generated sounds are the worst. I can happily listen to music or watch a video, but the sound of somebody talking or shuffling around somewhere in the building can be intolerable. Occasionally it gets so bad that in order to stay calm, I have to go outside and find a patch of grass to lay down on and listen to the ambient noises of crickets or a nearby highway.
• My tinnitus can get stronger during a migraine. I normally have a certain amount of constant audio hissing in my ears in the very high frequencies; during a migraine the range of frequencies can be lowered, and seems to shift around a bit on a timescale of seconds.
• Perhaps my weirdest sound-related migraine symptom is related to my music processor. Under normal circumstances I have music playing in my head around 80% of the day, and I can kind of pick what I want to listen to. When I have a migraine, one song might become much more persistent, and it'll shorten itself to just two or four measures looping indefinitely.
• Sometimes it becomes difficult to think effectively during migraines. Usually I can think and work just fine during a migraine, but occasionally I'll just be completely unable to focus on anything productive.
• Finally, I do sometimes get head pain during migraines, though it is usually mild unless I've had an especially stressful or active day.

Migraines are pretty weird. They're something like the equivalent of an electrical storm in the brain. They show both neurological and vascular abnormalities, though it is unknown which system is the cause. Most authorities classify the symptoms of migraines according to what phase of the migraine they come in, but I've never paid much attention to the course of my migraines. All I am aware of is that I only have some symptoms at once, and irritability frequently precedes other symptoms by hours or a day.

Sometimes migraines can be "triggered" by a particular taste or smell or other sensation. For me the most common culprits are cars, monosodium glutemate, and cheese (especially half-melted cheese). Unlike most adverse food reactions, migraine triggers are associated with the taste of food rather than its nutrition. I'm not sure whether migraine "triggers" actually initiaite migraines. It's possible they just aggravate the headache of the migraine, and are only active once the migraine process has already begun (though the migraineur may not have noticed it yet). I suppose that would make them akin to light and sound sensitivity.

Some people suffer mightily from their migraines. I am fortunate enough to be only inconvenienced by them. There aren't many good ways to treat migraines. Traditional pain relievers can be a little helpful. Counterintuitively, stimulant drugs tend to reduce the effects of migraines and alcohol makes them more severe. Back when I was a regular caffeine drinker, caffeinated drinks would sooth my migraines somewhat; however, since I stopped drinking caffeine entirely three months ago, my migraines have become less frequent and severe.