One of the most successful home computer systems of all time was the Commodore 64. While the Apple II broadly targeted businesses, homes, and schools, the Commodore 64 aimed itself perfectly at home users. Its graphics and sound capacity were well in advance of any other computer of the 8-bit dawn. I used my Apple IIc for term papers and databases, but I hogged my roommate's Commodore 64 for games. Although remnant C64 hardware is hard to come by, and most vintage 1985 floppy disks have long since gone to silicon heaven, the Commodore 64 lives on in emulation and borderline-legal disk images. CCS64 (free) is one such emulator.
CCS64 is a well-supported and very complete emulator, with a few minor quirks--many of which stem from its very desire to be the perfect emulator. It makes few concessions to the idea that it's running under Windows. While you use the menu bar to bring up options and settings, those screens are shown in the emulator, using C64 style navigation functionality--there are no radio buttons and checkboxes here, bucko! I experienced considerable frustration getting the joystick emulation to work, until I discovered that I need to specify both the key mapping and set the input for the game port to use that mapping. The help documentation is very sparse. Fortunately, there's a well-populated forum on hand to answer many questions. CCS64 is aimed fairly heavily at long-time Commodore users; there's little hand-holding for those not intimately acquainted with the platform and its conventions.
Once you've got it working, though... well, it's a Commodore 64. CCS64 runs exactly like a standard model, including speed and timing (since many programs relied on specific timing, including hardware response speeds, to function.) It can, thus, take a while to boot from a floppy (sadly, there's no karunk-runk grinding noise emulator). It can be a bit shocking to see just how primitive the graphics and sounds were. Those of you who haven't looked at older systems since they were cutting edge might suffer some cognitive dissonance as you try to reconcile your fuzzy memories with the harsh-edged realities.
To get any software to actually run on the CCS64 emulator, you will need to scrounge disk images from the net. These are not hard to find. To be perfectly clear, there is no such thing as "abandonware"--not legally. Either a copyright holder has given permission, or they haven't. Many of the easily located disk images are, amusingly, images of pirated disks, from back in the old days when "crackers" signed their work with revised startup screens crediting themselves.
If you're willing to put in a bit of effort to configure CCS64, and you want to re-experience the technology of the 1980s (or just see what Dad's talking about when he talks about how Halo III isn't anywhere near as cool as Impossible Mission), download it and check it out.