You guys, that's seriously like the second element on the periodic table. The Independent UK reports:

It is the second-lightest element in the Universe, has the lowest boiling-point of any gas and is commonly used through the world to inflate party balloons. But helium is also a non-renewable resource and the world's reserves of the precious gas are about to run out, a shortage that is likely to have far-reaching repercussions.

Scientists have warned that the world's most commonly used inert gas is being depleted at an astonishing rate because of a law passed in the United States in 1996 which has effectively made helium too cheap to recycle.
The Earth is 4.7 billion years old and it has taken that long to accumulate our helium reserves, which we will dissipate in about 100 years.

Helium, the article explains, is used for everything from inflating the dirigibles those steam punk kids all love to cooling MRIs and the Large Hadron Collider to scrubbing the fuel out of rocket engines. The money quote comes from one Nobel laureate professor Robert Richardson of Cornell University:

Professor Richardson also believes that party balloons filled with helium are too cheap, and they should really cost about $100 (£75) to reflect the precious nature of the gas they contain.

"Once helium is released into the atmosphere in the form of party balloons or boiling helium it is lost to the Earth forever, lost to the Earth forever," he emphasised.

(hat tip: Mackro)