Open Office is one of my favorite open source desktop applications. Not only is it competitive with Microsoft Office, it is portable. Schools that use thumb drives for student files may find it interesting to put a portable version of Open Office on the thumb drive. It means that a student can have all the Open Office settings and customizations on the same drive as the files. It also means that when the student goes home, the same application will there on the home computer. This is one of the more significant issues with good, but not commonly used, software. This portable version runs from the thumb drive and thus does not require any installation on the host computer.
Unfortunately, this system does not work on Macs. Of course, you could always take a copy of Open Office as an install file, but installation on every computer is not a good solution.