Helium is a light inert gas and the second most abundant element in the universe. Helium is extracted from natural gas. In fact, all natural gas contains at least trace quantities of helium which is perhaps why we laugh at farts.

Aside from filling balloons, helium can also be used as:

1. a way to change your voice
2. an inert gas shield for arc welding
3. a protective gas in growing silicon and germanium crystals and producing titanium and zirconium
4. a cooling medium for nuclear reactors
5. a gas for supersonic wind tunnels
6. an artificial atmosphere for divers (when mixed with oxygen)

Sources: Los Alamos National Laboratory, CST Division