(Free photo thanks to bigphoto.com; ours didn't turn out this well)
For some science about how lightning works, see this site. And if you enjoy mythology and cultural stories, you may recall that the thunderbolt is a symbol of power which is present in many world myths. It is symbolic of a loss of ignorance and/or of destruction, or retribution. It is still used today, especially in military symbols or pictures. And in language, both French and Italian use a phrase for "love at first sight" that translates directly in English to lightning strike.
No matter how you look at it, lightning is pretty awe-inspiring.