I have a personal connection when it comes to epilepsy because my college roommate (and fellow milwife) Erin, has it. Living with her gave me a perspective and an understanding of the illness that has stayed with me. The frequency and specific physical reaction can vary widely from person to person. In fact, most people who see Erin have a seizure wouldn't even know it was happening. Her lips turn blue but other than that, to someone who didn't know her well, she would almost appear to be daydreaming. The biggest problem was that she would still function mindlessly while having a seizure. In fact, on more than one occasion she would be walking home from class, go into a seizure and come out of it blocks away having no recollection of how she got there.
An organization called PAWS With A Cause was able to give her more independence and all those who care about her peace of mind by training a beautiful dog as her seizure assistance/response dog...specifically blocking her at every stair case and street curb. He was trained to only move when she gave a verbal command which can only happen when she isn't having a seizure.
Take some time this month to educate yourself and your children about epilepsy (and while you're at it, about service dogs-they're not just for the blind). And check out the Now I Know video campaign at the Epilepsy Foundation for more information and ways you can help.
For specific information on what to do if you see someone have a seizure, check out the first aid section of the Epilepsy Foundation website.