It's a bootable version of linux for people who want a change or like linux better (wat.) I find it useful for Impressing people at School (and the teachers allow it.) Also repairing computers that 4 year olds forget up. What do you use it for?
Link to pup-4.3.1.iso:
http://puppylinux.org/main/index.php?file=Download%20Latest%20Release.htmLink to unetbootin:
http://unetbootin.sourceforge.net/Additional Information: I'm typing this with it right now!

FAQ;
Q.I'm not installing this on my harddrive.
A.You don't need to! It boots off a flashdrive!
Q.How big does the flashdrive need to be?
A.Anysize, I recommend around 100MB, because you'll need another to save documents on.
Q.Is this a virus?
A.No, how the forget can a trusted sight have a virus?
Q.Can this GET viruses?
A.As I mentioned earlier you need another flashdrive to save things on, so you can't infect your main flashdrive.
Q.How does this boot on my computer?
A.Copies itself to your RAM and deletes after shutdown.
Q.Is this a question?
A.A bad one.