In a game of Halo 2 or 3 when in a situation of two on one where players A and B are on the same team and X is on the opposing team. Player A engages in a fire fight with the opponent (player X) lowering their shields substantially and in the process losing most or all of their shields. Before player A is killed he retreats into a room or cover and player B emerges a half moment later. Player X believes that he is being faced with the same enemy and moving in for the kill. In reality he is at a disadvantage and is killed by the fully shielded player B.

The policy used by Bell Mobility to get more money out of their customers. They will *bait* you in with offers of really good stuff, then switch the offers around behind your back, often with the excuse of "that was just a promotion" or "you must have changed it yourself"

When a fairly attractive woman or man introduces themeselves to a group of the opposite sex in order to get their ugly friend in the door

the term can also be used for a relationship when a girl or guy "advertises" her or himself as being something s/he's not and in the end ends up being a shoddier "product" -- a lesser person than was originally promoted.
for example a guy might start out being really attentive to a girl he wants to go out with: lots of emails, text messages, dates, flowers etc... and then once the girl has committed to the guy in some way he turns off the attention and hardly ever calls, no more flowers, hard to get hold of etc...

The process by which a girl procures a free drink from a man at a bar, and then escapes awkward conversation by pawning him off on her friend.

Scientology with less religion, defined by the economic advantage of conning in a customer (or oftenly 'sucker') by teasing them in with a deal or other great benefit but then as they are about to pay the deal are told that the original product is not available but that a substitute is. They then employ the people to then buy a more expensive item. The original product is never revealed to the person, it is an easy economic trick

When a designated driver says he will bring every one home from the bar, and then precedes to drink himself into a vomiting stupor. So that it is obvious he is the only one who can't drive.

Be fucking a girl from behind, either anal or vaginal, and then pull out. Have a friend step-in for you and begin to fuck her. Walk outside and stand by the window. Have your friend angle her toward the window so she can see you. Take a picture of her reaction.
Notes: The room needs to be very dark, and it is helpful to put your girl's face in a pillow so she is unaware of the switch. Two cameras can be used as well; one for you and one for your friend.