You maybe already know that TinyCore is the smallest Linux distro, it takes only 10MB of disk space, however it does not contain any applications. Other well-known small Linux OSes include Puppy Linux, Slax Linux and Damn Small Linux, they are pretty but takes more than 50MB of disk space.
SliTaz GNU/Linux is an amazing Linux os which is only 30MB in size, it has a GUI interface and ships with dozens of useful applications including a lightweight web browser called Midori, PCMan File Manager, a text editor called LeafPad, GParted partition editor, ePDF pdf viewer, Alsamixer volume mixer, Alsaplayer audio player, Asunder cd ripper, mtPaint image editor, Beaver code editor, LUA interpreter, GColors color selector, SSH client and server, etc.
SliTaz allows to create a bootable live USB stick for itself, it can also be installed to local hard drive.
After you’ve downloaded SliTaz, you can boot from the iso file in your favorite virtual machine like VMWare, VirtualBox to enjoy it without bothering your CD/DVD drive.
Visit the official website at http://www.slitaz.org/en/.