As a GM, many a time I run into a situation that I know nothing of, am not prepared about, and need something, NOW! Maybe it is a freeform adventure and plot was not prepared, maybe I prepared some plot, but the characters chose completely different direction to go into, maybe they just went to a pub while on their quest, and I have no idea what is in this casual non-campaign-significant pub.
I have discovered the One Sentence NPC contest results priceless for such situations. On the other hand, the printed adventure plots and detailed NPC-s are useless to me during play - I find them useful only before the session, when I am preparing.
I think another example of a tool I am looking for are name generators. Yet another is the List of Forest Threats.
What other tools could be used to create in real time adventure scenes? Note that using a PC is not real time, though I do have a printer.