Waze is a community-based traffic app that I use quite a lot in L.A. They have a special initiative going on just in time for Halloween and that's a haunted maze map. Basically anywhere that hasn't been scoped out by users is "haunted." Now help de-haunt the map by taking photos and basically helping them flesh out the map. According to the press release "Every place added helps reduce the amount of haunted places, and every real place equals points and bragging rights." According to me "Every place added helps us generate content thanks to you, and also we're tracking your movements because content is king."
Something else that's really cool, though-- for a limited time, the Waze navigation voice is done by none other than Ichabod crane from Fox's Sleepy Hollow. I wish they would have just left it there instead of making us their guinea pigs/gophers for filling out their maps but it wouldn't be a free app if you didn't pay for it somehow.
Happy Halloween!