Here's an Idea I have for the next game: Collectable files.  
  
Much like permaperks, these little files spawn randomly, at any point, in any game mode.  
The difference is: Files once collected do not effect your game, but instead return to one's basic menu, where one can read up on the files they collected.  
  
  
There would be all kinds of files for all kinds of things:  
  
Surivers:  
Marelton Johnson 
Samuel J. Stulenger 
Russman 
Abigail "Misty" Barrington   
"Tank" Dempsey 
Nikolai Belinski 
Takeo Matsaki 
Doctor Edward Richtofen  
  
Controllers:  
Doctor ludwig maxis 
Doctor Edward Richtofen 
Samantha Maxis 
??? 
  
  
Drops:  
Carpenter 
Double points 
Nuke 
Max-Amo 
Insta-kill 
Fire Sale 
Zombie blood 
  
  
Perks:  
Juggernog 
Double tap (2.0)  
Speedcola 
Quick revive 
Deadshot Daquiri 
PHD Flopper 
Staminup 
Mule-Kick 
Electric Cherry 
Vulture's Aid 
The wonderfizz 
  
  
Map findings:  
Collected via map discovery: Adding the hatch to the diner, finding the cabin in the woods, feeding all 3 dogs, killing all the crawlers without missing, entering the ghost house, entering a robot, ect. Once it's been done, it is added into this part of the book.  
  
Zombies:  
Normal (Shows variants of normal zombies)  
Armored 
Flaming  
Crawler 
"Him"  
Nova-Jumper 
Brutus 
Ghosts 
Panzers 
Argarthian Templars 
  
Weapons:  
Not even going into it... 
  
  
  
  
  
Now to collect information on each of these subjects is different:  
  
Map findings can only be completed once one fulfills the unknown task: Just look around, experiment, and find things.  
Drop notes can be collected from file-drops: Drops that look like files. The files collected will go towards the type of drop on the map: No carpenters, no carpenter information. Furthermore it takes multiple drops to get a full page of a file to read.  
Zombie notes are gotten from experience killing zombies, getting hurt by zombies, and avoiding a zombie's attack.  
Weapon notes are taken from one simply using the weapon enough.  
Perk notes are taken actually from the wonder fizz, sometimes after receiving a perk, the WF will leave a note as residue in it's chamber, collect it for info.  
Surviver info is collected from playing as that surviver longer.  
controller info is gained from playing a map with that controller.  
  
  
  
These files also contain one's total kills, head shots, downs, deaths, games played, doors opened, perks drunken, highest rounds on each map,rank among world wide players, AND can be viewed by other players in a lobby.