Okay, so there are some people that prefer using UNIX (That's Mac OS X, GNU/Linux, the BSDs, etc) to Microsoft Windows. In that case, you need to use a program called Wine to play. If you like using the command line interface, like I do, here's a guide to getting Ace of Spades to work, and play well:
(In these instructions, I am using ## in place of the version number. Remember to change this. Tab completes in most shells, but make sure you're in the same working directory of the installer if you don't want to type the full path out.)

chmod 755 aos*install.msi && wine start aos##install.msi
This makes the installer executable, and starts it.

nano ~/.wine/drive_c/Ace\ of\ Spades/config.ini
This is for changing your name. Nano is recommended for beginners, but any plaintext editor works.

echo "wine ~/.wine/drive_c/Ace\ of\ Spades/client.exe -$1" > aos && chmod 755 aos
This makes a small script you can use to start playing from the command line.

echo "wine ~/.wine/drive_c/Ace\ of\ Spades/server.exe" > aoserv && chmod 755 aoserv
...Alternatively, you can also have one that starts a server. I'd use this in GNU Screen.

sudo cp aos /usr/games
Now let's add this to our path. If this folder isn't in your path, see what is by typing "echo $PATH". You'll probably need privileges to copy the script there.

aos aos://16777343
When you want to play, just type aos and paste the server URL. This example would connect you to a server on your rig (localhost).

I hope this helps! Feel free to copy, modify, or distribute; it's public domain.

"Bob''