Reply #16: The Guardian has the clearest explantions I've read.

[snagglepuss]

snip

The Higgs boson is the last remaining piece of the Standard Model, the set of mathematical rules that describe how all the known particles in nature interact with one another.



snip


The Higgs boson is the signature particle of a theory that says the vacuum of space is filled with an invisible field that stretches to every corner of the universe. The field is thought to give mass to fundamental particles, such as the quarks and electrons that make up atoms. Without the field, or something like it, these particles would weigh nothing at all and hurtle around at the speed of light. There would be no atoms as we know them, nor stars or planets.






http://www.guardian.co.uk/science/2011/dec/09/higgs-boson-hunters-lhc