Why, only last night I overheard a forklift driver and an beauty shop operater wondering the very same thing. Scientists have turned back the biological clock in a yeast. This is being hailed as important advance, at least by the NY Times:

Now in a slick feat of molecular maneuvering, a team of researchers has reorganized huge portions of one yeast species' chromosomes, rendering its chromosomal map identical to that of a closely related species, just as it was once, in the distant past....

"People were always saying, `Wouldn't it be great if we could undo this and see what happens,' and here they did it and saw an effect," said Dr. Mohamed Noor, an evolutionary biologist at Louisiana State University. Full story