The Scientific Explanation for 
Deja Vu (via 
Wikipedia):
Déjà vu (
French pronunciation),
 literally "already seen") is the experience of feeling sure that one 
has already witnessed or experienced a current situation, even though 
the exact circumstances of the previous encounter are uncertain and were
 perhaps imagined.
The term was coined by a 
French psychic researcher, 
Émile Boirac (1851–1917) in his book 
L'Avenir des sciences psychiques
 ("The Future of Psychic Sciences"), which expanded upon an essay he 
wrote while an undergraduate. The experience of déjà vu is usually 
accompanied by a compelling sense of familiarity, and also a sense of 
"eeriness", "strangeness", "weirdness", or what 
Sigmund Freud calls "the 
uncanny".
 The "previous" experience is most frequently attributed to a dream, 
although in some cases there is a firm sense that the experience has 
genuinely happened in the past.
[1]
The experience of déjà vu seems to be quite common among adults and 
children alike. References to the experience of déjà vu are found in 
literature of the past,
[2]
 indicating it is not a new phenomenon. It has been extremely difficult 
to invoke the déjà vu experience in laboratory settings, therefore 
making it a subject of few empirical studies. Certain researchers claim 
to have found ways to recreate this sensation using 
hypnosis.
[3]
Scientific Researches
The most likely explanation of déjà vu is not that it is an act of "precognition" or "prophecy", but rather that it is an anomaly of memory, giving the false impression that an experience is "being recalled".[4][5]
 This explanation is substantiated by the fact that the sense of 
"recollection" at the time is strong in most cases, but that the 
circumstances of the "previous" experience (when, where, and how the 
earlier experience occurred) are quite uncertain or known to be 
impossible. 
Likewise, as time passes, subjects can exhibit a strong 
recollection of having the "unsettling" experience of déjà vu itself, 
but little or no recollection of the specifics of the event(s) or 
circumstance(s) they were "remembering" when they had the déjà vu 
experience. In particular, this may result from an overlap between the 
neurological systems responsible for short-term memory and those responsible for long-term memory
 (events which are perceived as being in the past). The events would be 
stored into memory before the conscious part of the brain even receives 
the information and processes it.[citation needed]
Another hypothesis being explored is that of vision. The hypothesis 
suggests that one eye may record what is seen fractionally faster than 
the other, creating the "strong recollection" sensation upon the "same" 
scene being viewed milliseconds later by the opposite eye.
[6]
However, this hypothesis fails to explain the phenomenon when other 
sensory inputs are involved, such as hearing or touch. If one, for 
instance, experiences déjà vu of someone slapping the fingers on his 
left hand, then the déjà vu feeling is certainly not due to his right 
hand experiencing the same sensation later than his left hand 
considering that his right hand would never receive the same sensory 
input.
Also, people with only one eye still report experiencing déjà vu 
or déjà vécu (a rare disorder of memory, similar to persistent déjà vu).
 The global phenomenon can therefore at least in certain cases be 
narrowed down to the brain itself (i.e., one hemisphere being late 
compared to the other one).
See Twilight Zone (1959), Season 1, Episode 10: Judgment Night
(available now on 
Netflix Instant Play - I am undergoing a Twilight Zone Marathon... 138 Episodes!).
This is a great opportunity to throw in one of my all-time favorite videos/songs (Actually the video is kinda dorky - oh so 80's! Do you remember it?):