Lightning Strikes Twice
Author: Dan Katz

Of course, these are all quotes from the Back to the Future movies.
There are two logical orders these quotes can be put in; the easiest
is in order as seen in the movies (aka the order Marty experiences
them in):

logmbfuqcskhjpvnditear

Rearranging the grid in this order we get:

l) UVEFPIGSITNSLABIOSOTOB
o) FSHSNCOFREAIRYECNLTPCS
g) PEIASMPUWEIATOHCUIARNT
m) TEZNBPTSRNZMSBRNHEDLBU
b) EISXGWOAZTEYEICILANCOP
f) BLMTUTRNEITDESCDBNNESL
u) SCOEFOHTUANAJSICTGRSLE
q) MARFRKEEQVADMRDROILUCU
c) WAOYPEHMOPCEEJTSNFOTRM
s) MTNOCIVWCTWOKYULGRDFWS
k) LSLGJOLOEDHHOLIOAPHIUO
h) EHNHEPEIVJMEMIATXHATWU
j) WISCLEADODLAROWJCODNSU
p) DESIWOPLEOSRTDTDRIEIPY
v) EOSEYNMCULNBTEIEMNEXDO
n) RAHREWNBEKCRAPYANGIOYO
d) YDAFEIUADURPEDNNGDKGES
i) UNTGELSQOUFOOBDREOAXZE
t) LSIKNAHOSOIFHDETIANOTP
e) PECIFWSZACONSDAOTJOABD
a) LGTABERAGMESOTYRATSDLR
r) GIBNUERBAMTABRSEEOTIHS

The other order we can put them in is chronological order by date and
time, which gives:

teagmjbfpuvqndilokhrcs

Rearranging the rows this way, we get:

t) LSIKNAHOSOIFHDETIANOTP
e) PECIFWSZACONSDAOTJOABD
a) LGTABERAGMESOTYRATSDLR
g) PEIASMPUWEIATOHCUIARNT
m) TEZNBPTSRNZMSBRNHEDLBU
j) WISCLEADODLAROWJCODNSU
b) EISXGWOAZTEYEICILANCOP
f) BLMTUTRNEITDESCDBNNESL
p) DESIWOPLEOSRTDTDRIEIPY
u) SCOEFOHTUANAJSICTGRSLE
v) EOSEYNMCULNBTEIEMNEXDO
q) MARFRKEEQVADMRDROILUCU
n) RAHREWNBEKCRAPYANGIOYO
d) YDAFEIUADURPEDNNGDKGES
i) UNTGELSQOUFOOBDREOAXZE
l) UVEFPIGSITNSLABIOSOTOB
o) FSHSNCOFREAIRYECNLTPCS
k) LSLGJOLOEDHHOLIOAPHIUO
h) EHNHEPEIVJMEMIATXHATWU
r) GIBNUERBAMTABRSEEOTIHS
c) WAOYPEHMOPCEEJTSNFOTRM
s) MTNOCIVWCTWOKYULGRDFWS

The indicated diagonals of these two grids read

USING THE OTHER DIAGONALS
LET A BE ONE AND ADD IN PAIRS

The opposite (unmarked) diagonals read, from lower-left to upper-right:

GGCKEINCEDMHKJDCBADRCB
MABHJCGQDKABJDCICEADBP

Taking these and adding them pairwise (A=1, B=2, ...) we get:

G + M = T
G + A = H
C + B = E
K + H = S
E + J = O
I + C = L
N + G = U
C + Q = T
E + D = I
D + K = O
M + A = N
H + B = J
K + J = U
J + D = N
D + C = G
C + I = L
B + C = E
A + E = F
D + A = E
R + D = V
C + B = E
B + P = R

Thus, the solution is JUNGLE FEVER.