List single player playthroughs that you thought were a lot of fun when you played them.
Here's mine:
Battlefield Bad Company 1 (It was a lot of fun for me)
Halo 3: ODST
Super Mario Sunshine
Metal Gear Solid: Snake Eater
Call of Duty 4 on Veteran
Modern Warfare 2 on Veteran
Splinter Cell Double Agent
Saints Row The Third
Battlefield 3
That's all I can think of, now post yours.