LinuxMint is a flavor of Linux, a free operating system (as opposed to commercial OSs such as Microsoft's Windows and Apple's OSX). A flavor means a team of programmers or a company packages the Linux OS and gives it a distinct flavor (logo, installer, package manager, themes, etc). You could liken it to a particular cellphone sold by different cellphone companies; with the difference being the cellphone will have the provider's logo, network technology (GSM, CDMA), etc. In short, it's the same phone.
The installation (partitioning, choosing timezone, creating user & password, etc) took about 10 minutes, and it was very easy (it's in graphical mode). The whole installation took about 2.5GB of space (contrast that to Windows which requires at least double). It installed more than enough software that one could need.
After you login, this is the default desktop:

LinuxMint has an intuitive and elegant menu (you can search a program you're looking for in Filter):

This is the file manager

The side panel on the left side lets you browse and manipulate directories, files, pictures and documents in the hard disk, other partitions, USB drives, CD/DVD drives, etc.
Firefox is the default browser (but you can add Opera and Google's Chrome). Browser plugins work out of the box (without needing to install extra). Apple's quicktime:

Adobe's Flash:

For Office, the system comes with OpenOffice and includes Microsoft's versions of Word, Excel & PowerPoint. This is OpenOffice's Writer:

Overall, LinuxMint is a nice (eye candy) flavor of Linux. It's easy to use it, update it (it has an updater similar to Windows Update) and has a repository with thousands of free software including games such as LBReakout2:

If interested, you could give LinuxMint a try.