Antivirus software is so serious--how about a little fun? If you use Avast antivirus software to monitor your PC, you can also download a variety of skins (e.g., Spider-Man, ones that look like a Mac) for your antivirus software at the Avast Web site. There's also a tutorial on creating your own skin.
http://www.avast.com/eng/skins.html
You can either save the skin or have Avast open with the new skin.