Windows: If you're setting up a new system or helping a friend to see how much great free and open source software exists, ZeuAPP is a portable installation tool for nearly a hundred applications.
ZeuAPP is essentially an installation dashboard for 82 applications. You can navigate to application types like CD Burners, P2P apps, Office apps and more. Under each tab are applications for that category with a "Download" and "Visit Website" button which allow you to download the application and automatically launch the installer or visit the web site for more info.
ZeuAPP is freeware, portable and Windows only. Have a favourite tool for batch installing your favourite apps? Let's hear about it in the comments.