Hi Crwstar,
A deja vu is a form of a simple partial seizure also known as an aura sz. I've had them many times especially right before a complex partial sz.
What happens to me is a get a nervous feeling in my stomach and then I start to see colors flashing back and forth in my eyes but I'm totally conscious and aware of what's going on around me. Sometimes I will smell an odd smell like deviled eggs, or something burning. I've learned the moment that I get the nervous feeling in my stomach to tighten up all the muscles in my body and make my hands into tight fists for a few seconds and this will stop the sz. I learned about this back in the 1970's from my neuro and it has stopped many of these sz. Here's wishing you well and May God Bless You!

Sue