My migraines are triggered by 3D films, stress, dehydration (can be caused by heat), smells and food combinations - oranges and chocolate, pastry and caffeine etc. The foods on their own are okay (so it's not an allergy) but a few in combination are a guaranteed migraine recipe. Smells that trigger for me are cinnamon, citrus, mothball smells and musk.
I start by feeling chilly, then a bit shivery, then the light sensitivity arrives. At this point I can catch it with some pink migralieve and a few pints of water (literally, glugging away for 15 min or so - proper gulps. DP is trained to bring in pint glasses of it to form a queue - 3/4 is usually enough). Whatever time of day or night it is, I mustn't go to sleep at this point (even though super tired and yawning - the migraine manages to sneak up on me in my sleep, even if I've done the water/pills thing.
If I don't get to the water/pills point within about 20 min of the first light sensitivity pains, the aura arrives. By then it's too late, and I'll have disturbed vision and vomiting for 3-5 days and have to retreat to a dark, cold room. I'm torn between envy and sympathy for those who can go into work - not me!
By the last day, the visuals are back to normal, and it turns into a fairly normal headache, except that it can slink around to different corners of my head (like a big black panther!) It often tends to rest around either ear, or between/behind my eyes. On the final day, I can mooch about the house and attempt conversation - HeathRobinson's example above was interesting as my language gets confused too, but I use words that sound similar but mean nothing related (A recent example was "I put the pug of tea on the able.")
Apart from the combined pill/cerazette thing, I've never spoken to the doctor as Migraines have always been in my family (mum's side) and I've had them as long as I remember... maybe there's hope that I don't have to lose a few days every time. Will need to look in to the "magic injections".