Non-tolerance describes a state of mind where anything outside the rules of acceptability are ignored or attacked. The rules of acceptability are generally based on ones own individual rules but can also be based on societies rule set. Usually (but not always) driven by anger and/or a lack of patience.
For example, non-tolerance of racism
or non-tolerance of some boy racer (or rice boy) who just cut you up in his mom's crappy Peugeot 206
Non-tolerance can also be extended to "non-tolerance day". A day when someone got out of the wrong side of the bed and declares war on everyone and everything!
Recently used by George Bush when describing Americas policy against terrorism. Note this is not the same as intolerance.