The most commonly-stolen item of weak public-schoolers, especially in lower-income areas where the schools do not put money on a computerized lunch account. At such a school, students have to bring in the necessary money each day to buy their meal, allowing bullies to steal money that they can actually use, as opposed to a check (is it spelled 'cheque'?).
Bearing refrence to the period of adolescent age when nerds would get beat up by the bigger kid for their lunch money. Thus, lunch money as an adjective can be used to describe anything not worth your time, or done poorly.
Another of way of saying "get owned". You can use this phrase when someone gets embarrassed or "owned" either physically or in conversation.
Graham: "what up playa"
Damian: "not much man, just got knocked down by some freshman"
Graham: "hahahah get your lunch money taken kid"
Damian: :( :( :(
1. The kid who grew up always getting the crap kicked out of him and losing his lunch money, but never turned the corner to become cool as an adult. If he were carrying books down the street, you would still knock them out of his hands and laugh.