ScummVM is Virtual Machine, that allows you to run adventure games created for a number of game creation engines. This is a great way of playing those classic adventure games that you loved so much, or never got a chance to play at the time. Some of them such as Beneath a Steel Sky have rarely been bettered and can provide hours of fun.
Supported Game Creation Engines
The virtual machine supports a number of game engines, but the most well known are:
SCUMM (Script Creation Utility for Maniac Mansion)
This, as the full name suggests, was written by Lucasfilm Games/LucasArts to make creating the game, Maniac Mansion, on the Commodore 64 easier. Because the game was created using the SCUMM engine, it made porting the game much simpler and hence found it's way to numerous platforms. This engine and later versions of it were used for other classic adventure games such as Zak McKracken and the Alien Mindbenders.
AGI (Adventure Game Interpreter)
ScummVM comes included with most of the popular Linux distributions. It is also available for lots of other platforms such as AmigaOS, Wii, Mac OS X, Windows and many more. There are pre-compiled binaries available from the download page of their site together with clear installation instructions.
Getting Games to Play on ScummVM
There are a few games that have been made available for free, and can be downloaded from the ScummVM download page. Alternatively you can look at the documentation on which files are needed to use your game with ScummVM. A full list of compatible games can be found here. The games are regularly sold on Ebay and some of them are available in compilations from Amazon.
I would begin by downloading Beneath a Steel Sky from the ScummVM download page. This is probably one of the best games available for it, and it is free. Hmm, have I mentioned Beneath a Steel Sky enough yet? No I don't think so, why not take a look at my article: Beneath a Steel Sky‚ My Favourite Graphical Adventure Game.