by the way, you cannot cover all such weird practices here; you dont have the space.

i am from the area, and i know a little bit. the village astrologer would have told that she would lose her husband early and remarry; to avoid that now she is married off to a frog. the frog will soon die, and then she will marry again when she grows up; voila!
the indian miss universe 1993, aishwarya roy, who is now a famous actor, married another famous actor (who is the son of another very famous actor, whew!) a few years ago. but before the ceremony she 'married' a banana tree, which was promptly cut down after the ceremony, thus rendering her a 'widow'; then she married the actor. as simple as that.

Loadedguns, Please check again, both you and neatorama are right! Nur Jahan was the favourite wife of Jahangir; Mumtaz, the wife of Shah Jahan (son of Jahangir), the inspiration for the Taj Mahal, was the daughter of the brother of Nur Jahan. Thus, both are right!