I wish to know, just for my general knowledge, what really constitutes blasphemy. I'm one of those always-shooting-my-mouth atheist types, and I don't wanna end up on the wrong side of a marauding South Asian mob.

Not that I'm going out of my way to enter a religious place or touch a religious book. But sometimes I have to show guests around churches and cemeteries, for example. What if touching isn't required and religious nutters are triggered just by words. What words must one not say in order to stay safe from blasphemy charges?