PARANOIA is a darkly humorous role-playing game published by Mongoose Publishing. I believe the back cover of the main book says it all:
The Computer Is Your Friend!
PARANOIA is an award-winning role-playing game set in a darkly humorous future ruled by a well-meaning but deranged computer.
The Computer is happy. The Computer is crazy.
The Computer will help you become happy. This will drive you crazy.
Being a citizen of Alpha Complex is fun. The Computer says so, and The Computer is your friend.
Many traitors threaten Alpha Complex.
Many happy citizens live in Alpha Complex. Most happy citizens are crazy.
Which are more dangerous - traitors or happy citizens?
Rooting out traitors will make you happy. The Computer tells you so.
If you are not happy, The Computer will use you as reactor shielding.
Being a Troubleshooter is fun. The Computer tells you so.
Do you doubt The Computer, citizen?
Troubleshooters get shot at, stabbed, mangled, incinerated, poisoned, stapled, blown to bits and accidentally executed.
This is so much fun many Troubleshooters go crazy.
You work with many Troubleshooters. They all carry lasers.
Aren’t you glad you have a laser too? Won’t this be fun?
Stay alert! Trust no one!
Keep your laser handy!
After this intro, how can PARANOIA not be fun? (And remember, having fun makes you happy. Happiness is mandatory; therefore, it is treason not to be happy. You aren’t a traitor, are you, citizen?) The basic premise of the setting is that your character is a Troubleshooter working for The Computer in Alpha Complex. As a Troubleshooter, your character is assigned missions and team duties to complete while keeping an eye out for traitors, mutants, or mutant traitors. What makes things really interesting and keeps players on their toes is that all of the player characters on the Troubleshooter team are mutant traitors... every last one. (Heh, heh, heh.) It does help that your character is a clone, so when he dies, a new clone is decanted and the game continues. Oh, and trust me, he will die. Hopefully, he can take down a few mutant commie traitors before he goes though.