An Olympic gold medal is almost 99% silver.

The first-place medal is actually 550 grams of silver covered with a thin layer of gold (6 grams)! A silver medal is far more authentic - 509 grams of silver and 41 grams of copper. The bronze medal is composed of mostly copper, with some zinc and tin mixed in. And approximately how much are all these precious medals worth, you ask? The gold - $494, the silver - $260, and the bronze...$3!

The annoying horn that plays during FIFA World Cup Matches is called a "Vuvuzela"

The exact origins of the vuvuzela are disputed, but they have been seen in South African football matches since at least the 1990s. It's become part of the South African football experience. The instrument is supposed to resemble the sound of an elephant, but thousands of them in a stadium make a sound reminiscent of a swarm of bees.
The origin of the name itself, "vuvuzela", is also uncertain. It might mean "making noise" or possibly a variation on the word "shower" because it looks like a shower head.

Listening to vuvuzelas for an extended period of time puts you at risk for hearing loss. You can lose hearing from listening to sounds at 100 decibels for only 15 minutes. The vuvuzela's sound is the equivalent of 127 decibels.