Gambit Psychology
A gambit, traditionally, is a pawn sacrifice in the early stages of the opening. There are many reasons that gambits are played: often to gain tempo, good/quick development, to weaken an opponent's position; but not many people realise the psychological aspect of the gambit.
Gambits (especiall obscure ones) can cause fear to the opponent: if they are unfamiliar with the particular gambit then they may become confused; they may beleive that they are falling into a trap; if they are unfamiliar to the gambit, then they will become MUCH more cautious, and spend longer on their moves, getting them into serious time troubles in blitz AND classic.
This can also have the opposite effect: (from beginner to amateur) it can well make the opposition over-confident, leading to the opposite style of play.
Gambits can also be a statement:"i'm not afraid to let you have this pawn," "I will beat you either way," sort of thing.
An example I can think of at the moment is what I intend to play against someone who is exploring the Sicilian, but I will play in a tournament game soon.
If you know an opponents pet hates then a gambit is also good.
That is all I can think of for the moment in the way of gambits, if anybody reading this article has any other ideas about gambits then feel free to post!