Do you want to write a book? Sure, we all do! Here are a few suggestions for topics that are currently not covered well in the world of books that are actually in print (updated as I think of stuff):

Boat and RV upholstery projects

Good tattoo ideas, including the meaning of mysterious symbols and characters

Phrasebooks and foreign language dictionaries aimed at eating in restaurants (see Chowhound’s translation card, we need more of this!)

Baby names in Vietnamese: specifically, American names with their meanings explained in Vietnamese.