Knoppix KDE 3.1 Linux boot-from-CD is available attached to a magazine "PCUTILITIES" from England, as well as a CD with 510 Windows utilities, at Borders Books for $10.95 + tax.
If it did not say Linux on it, it would seem to function like any GUI operating system.
It sets itself up on a ramdisk, but goes back to the CD to load and run programs.(I think it would help if you have plenty of memory)
With my 1.1GHz Celeron, the slight delay is not much bother, but the CD starting up and stopping reminds me of the days before hard disks when everything ran off floppy disks.