“ The PCs are accosted in a major city containing at least one famous fortuneteller / prophet of the future. They are informed that their as-yet-unborn child will (insert terrible evil), and that, although they are very sorry, the PC must be executed to keep this from happening.”
“ The Wizard-Brewers of the Old Empire stored memories in bottles of mead, passing their brightest ideas, most subtle magics, and most important decisions on to their heirs in bottles of oddly-flavored honey-wine. A cache of these ancient magical vintages has been unearthed, but does anyone dare drink from it? The ancient mead's creator is a complete mystery, as are the thoughts he left behind.”
“ While it is within your purview to write long-spanning histories of your world, it is largely unnecessary. If you are running an RPG, do this instead: make a bullet point list of important events that affect the world today, and mysteries that people still don't know. Let these fuel your adventures.”