Which number comes next in the following sequence?

As Im standing there, I see they have a little sign with pictures of things you are not allowed to bring on the plane anymore. And they have, like, little drawings: circle, line through it, No! One of the things you cant bring on the plane anymore is a bomb -- no, no, they had a picture, cant do it. And it was the classic cartoon bomb, like the bowling ball with the little sparky whip coming out of it. And then you might think, Oh, I got a way around that. Uh-uh, not so fast -- they also had a picture of the bundle of dynamite with the clock.