I recently saw Penn and Teller demo the old classic rattle bars effect on one of their TV appearances, and they taught the trick afterward. Of course, they taught the version that has been in so many beginning magic books (where there is an extra box that rattles hidden in the magi's sleeve). But magic never stands still, and so there is always a new method for classic tricks, and the Brass Rattle Bars is the gimmickless, self-contained version of the classic rattle bar effect.
This version is made in the USA, and is made to the necessary exacting standards that the gimmick requires. You can find imported versions of this effect that cost about $25-$35 retail, but my (unfortunate) experience with these has been that they just don't work very well. You can try one of these from another dealer, and when you find it still rattles when it shouldn't, you can ask him to take it back and refund your money. Maybe he will. Then come back here and buy this (more expensive, but worth it) model, because it works every time, without fail.
How it looks: the magi shows three brass containers (each about 1.75 inches long), and he shakes two of them -- no rattle -- and shakes the third container and it rattles. Now the three containers are mixed, and no matter how attentively the spectators watch, they never can find the container that rattles.
If you couple this with a presentation where you are offering $100 bills to the lucky spectator (if she guesses correctly), it can be very compelling. But no worries. With this model, you are in complete control of whether she finds the rattling container or not. The containers are cleverly constructed to allow this trick to be done without the old method's extra gimmick. No sleeves needed -- perform this at a nudist colony, if you get those gigs!