Strange unidentified sound playing at random intervals I luckily managed to record the odd sound especially considering it plays at random. 

Two weeks back it played about 4 times, one minute apart. Then there was nothing for a long time and now it has returned again. Two times so far today at roughly a half hour apart. 

I have the following third party tools running in my top right toolbar: 


BetterTouchTool
Screenflow
Skype
Dropbox
VMware
BootChamp


I have the following programs running in my dock:


Chrome
Minecraft
iTunes
Skype
ScreenFlow 
Finder (of course)


Is there any app that would help me track where the sound is coming from? 

It's creeping me out? Is it possible it is a virus? If so, what is a good, free antivirus software for Mac?
I would guess that it is coming from Minecraft.  Try playing all the sounds in the ~/Library/Application Support/minecraft/resources/ folder and see if one is what you are hearing.

Be aware that the Library folder in your home folder is hidden by default.  To easily get there, choose the Go>Go to folder menu option (or press shift-command-G) and paste in the ~/Library/Application Support/minecraft/resources/ path.