A is for the Adelphous star system.
B is for Bajoran Boobs.
C is for Cardassian occupation forces on Bajor.
D is for Darmok.
E is for Enterprise, the series. Where we finally got to see official Starfleet underwear. Alot.
F is for Fesarius. Flagship of the First Federation.
G is for Gorn territorial claims to Cestus III.
H is for Holodeck malfunctions.
I is for Intrepid class starship. With it's magic shuttlecraft and torpedo replicator.
J is for Jem'Hadar drug addicts.
K is for the Klingon First Empire.
L is for Landru.
M is for Malcom Reed. Tactical officer of the Enterprise NX-01. And founding member of the "T'Pol's nice bum" fan club.
N is for Nog's personal effects auction to help fund his trip to Earth to enter Starfleet Academy.
O is for Omega molecules.
P is for Platonius.
Q is for Quasar-like phenomenon.
R is for Romulan spies infiltrating Vulcan during the mid-22nd century.
S is for solar chorona. The best hiding place ever for a starship with metaphasic shields.
T is for Tholian energy web technology.
U is for Universal translator.
V is for V'Ger.
W is for William T. Riker. "Fear the beard!"
X is for Xindi Xylophonists.
Y is for Yellow Alert.