Hi all,
I like the point spend system of Gumshoe and it inspired me to try a new thing with my group last time we played and I thought I'd share it with you. The party was about to enter a trading post-fortress that they knew almost nothing about beforehand. Besides main plot points I left the details very vague and decided that I would try to encourage my players to make the place come alive.
What I did was I gave each of them two tokens and told them they could play these at any time outside of combat. Playing a token would earn them the right to narrate almost anything into to the scene. I told them I wanted their input to make the place more interesting and intimate and they could use a token to narrate an NPC, a location, a custom etc. within the trading post (within reason naturally and I had veto rights). Playing a token would also net them an extra 20 XP for good roleplaying (we are playing 2nd edition).
It worked rather well. For example, right as the PCs came to the gates one of them chose to make the gatekeeper an old warbuddy. Suddenly, they got an easy, and free, access and a contact in the city. In another instance a player narrated a cool history for a Dwarf made window that served no other purpose but to add to the character of the place. Of course, some players took to it more than others but no one tried to abuse the system. I probably don't make a recurring thing but it suited a single, closed location rather well and served as an interesting change of pace. 3rd edition dice probably offer more options to this sort of thing.