Means, a lot of people are making demands on my time right now and your request may or may not get granted depending on if and/or when I get a chance to get to it.

a reply. used when one of many people ask you to do the same thing.

The reply to a statement, implying that there are many others with the same feeling.

Figurative: "If you want to discuss this topic with me, you will need to wait your turn, as there are any number of others who wish to do so who got here before you did."

Comes from a line control mechanism that is found today with decreasing frequency, where one is requested to take a numbered ticket from a strategically placed dispenser and accordingly wait for that number to be called.

Take a number means (more or less) "wait your turn." More often, its used to let someone know that a lot of other people want what they want.

What you say when several parties want to talk/complain to you about some presumed important matter.

the reply you get when you try to pick up a chick and she doesn't dig you at all.

means: before i do you, i'd do a whole bunch of others.

short for: "take a umber and wait. forever!"