Years ago they asked around in an Electronic Gaming Monthly magazine what the one game a person would want to get stranded with if they ship wrecked on an abandoned island.

Logically people were picking games that featured heavy to limitless replayability.

I thought that we could start of list of PC titles that boast randomly generated campaigns and variety in game play to the point where you could always leave them installed and they would never get old.

The ones on the top of my head are:

-Magic the Gathering
-Marvel Trading Card Game
-Montjoie!
-M & B: Warband (+ MODs)
-Anno Series
-Civilization Series
-A Valley Without Wind
-Star Wars Battlefront II (+ MODs)
-Star Wars Empire at War Gold (+ MODs)
-Space Rangers 2 Reboot
-SPaZ
-Darklands
-Mine Craft, Terraria, MicroTale, Space Bit
-Depths of Peril, Din's Curse
-Blood Bowl Legendary
-Star Flight Series
-UFO Afterlight

Morrowind is the obvious choice for me, since it's both my favorite game of all time AND massively endless. I have put 400 hours into that game and still never finished some of the questlines.

If I'm allowed a longer list, throw in Skyrim and even Oblivion, plus Gothic 3 and all the Fallout games. I guess if I get bored of RPGs I can hunt coconuts.

Tropico.

Either this: http://www.totaljerkface.com/happy_wheels.php
or this: http://deadwhale.com/play.php?game=774

I'm just listing games available on GOG that'd make great candidates in my mind:

Master of Magic
Master of Orion 2
Age of Wonders: Shadow Magic
Rollercoaster Tycoon 2
Heroes of Might & Magic 3 Complete
Sim City 2000
Alpha Centauri
Wing Commander: Privateer
Unreal Tournament '99
Worms
Pro Pinball series

Morrowind, Hearts of Iron III and Astrot*t

Defintie Ace for the link to Happy Wheels. XD

tropico
zeus
dungeon keeper 2
left 4 dead 2
stalker

UFO: Enemy Unknown
Sid Meier's Pirates!
Civilisation