I’ve played PAYDAY the last few weeks, it is a 4 player CO-OP FPS (think of Left 4 Dead in a different setting). One of the maps has caused me a bit of difficulty (Diamond Heist). There is an achievement called “Are Those The Blue Ones?” where you have to collect all the sapphires before the alarm goes off, and I kept forgetting where they were. Also keeping track of the cameras was a bit of a pain, so today I threw them all together on a map for easier reference (right-click “Save link as …” to download):

Graphics sources:
http://www.overkillsoftware.com/payday/
http://openclipart.org/detail/125695/diamant–diamond-by-lmproulx
http://openclipart.org/detail/31891/surveillance-camera-by-maxim2