As a kid, I always loved swinging, the higher the better. Eventually I got to wondering, after remembering watching that episode of Recess when I was younger, if I swing high enough, can I go over the bar? Is it even possible? (Episode in question:)
Well, it turns out you can, but not on a normal swing (fast forward to around 2 minutes) :
Since most people don't feel like making their own swing here's what happens on the normal kind:
On a regular playground swing that has chains, as you reach the peak of the curve, the chains slacken and gravity will send you back down. There isn't enough momentum to keep the swing moving fast enough to complete the arc. Sorry kids, the dream is gone.