Tiny Core Linux
Tiny Core Linux is probably the smallest Linux distribution available. It is being developed by Robert Shingledecker (of Damn Small Linux fame) as "a nomadic ultra small desktop capable of booting from cdrom, pendrive, or frugally from a hard drive".
This is a Learning by doing module.
Go to http://distro.ibiblio.org/pub/linux/distributions/tinycorelinux/release/ and download either bootfloppy.dd or preferably tinycore_1.4.iso. You'll need to copy these as bootable images.
NOTE: If you are new to Linux and working from a Windows® machine you should learn about RaWrite.
After you burn it you can learn it! TCL doesn't need your hard drive to run. It runs from RAM like a live CD. Just leave the disc in the drive and reboot your computer. You may have to go into the BIOS and change the "boot order".
Compare these with Basic commands in Linux.
Notice that your command prompt looks something like this:
The tilde (~) indicates that you are in your /home directory. Earlier, you used the ls command to list the contents of the /bin or binaries directory. Now use the cd command to change directories to /bin.
Now your command prompt looks like this:
Now type ls with no arguments (just hit "Enter"). The resulting list is the same. Type cd with no arguments and you'll be taken back to your /home directory.
Clicking on the middle icon on the desktop opens a set of buttons that allow you to setup and configure common functions and run various utilities. See a brief summary, Control Panel and a screenshot from wiki.tinycorelinux.com.
To download apps using the app-browser. Open app-browser and click apps -> cloud -> browse. This will load a library of app you can download, from there you can also search for apps. once you have found an app you want change the "Onboot" option to "download+load". let it download and done. :)