OK. I just got hired for a 6th grade birthday party(as a magician). I am 13 and they are 11. This automatically makes them hecklers(trust me on this one). I need some one-liners that aren't mean, don't put them down, and actually work, but are humorous at the same time. Any suggestions? Oh, and any suggestions for tricks I should do also?

Well it is hard to plan one liners when you don't know in which way they may heckle you, my advice is to read up throught these forums and remember some of the good ones for each situation. For younger people I would probably do sponge balls and make sure that you don't really do gimmic tricks because it is likely they will be grabbing your things. Hope this helps dude!

You have to improvise off of the moment.

No, here's what you say. If you mess up, just say "You know what kids, I just got real lazy and didn't want to use my real magic, therefore I tried it without magical powers, but this time, I'll show you with magic" It works 99.999999999% of the time!

That will NOT work. Eleven year olds are past the stage where they believe every little thing you say. They are beginning to lose their innocence. The best advice is what JGC2003 and KyletheGreat said. Read up on other threads in this forum and try and improvise in a situation. I can guarantee you that it'll end up being funnier and work better.

IF you can't handle crowds, don't do shows that you're paid for.