ScummVM is a program which allows you to run certain classic graphical point-and-click adventure games, provided you already have their data files. The clever part about this: ScummVM just replaces the executables shipped with the game, allowing you to play them on systems for which they were never designed!
The games are copyrighted so you'll only be able to play those you own.
More information on ScummVM can be had from the official site
Monkey Island 2
To be able to play Monkey Island 2 you need to pass ScummVM a parameter:
root@fic-gta01:/$ openmoko-scummvm --boot-param=10001 monkey2
For easy access from the menu you can create a menu entry by creating the file /usr/share/applications/monkeyisland2.desktop with the following content:
[Desktop Entry] Encoding=UTF-8 Name=LeChuck's Revenge Comment=Monkey Island 2: LeChuck's Revenge Exec=openmoko-scummvm --boot-param=10001 monkey2 Icon=monkeyisland2.png Terminal=false Type=Application Categories=Application;Game;AdventureGame; StartupNotify=false