But aging for most isn't about a rapidly degenerative disease like ALS. Most of us face aging on our 30th, 40th and 50th birthdays -- when we yearn for the carefree days of youth.

CNN: Tuesdays with Morrie

What gets them pumped up is the prospect of spending their days considering topics such as youth unemployment, global warming or the pitfalls of fiscal stimulus versus the drawbacks of austerity at a time of mounting deficits and widespread economic strife.

BBC: Davos 2013: 'Dynamic resilience' in a volatile world

The heady days of 50% annual growth are gone, but so are the sins of youth--uneven financial performance, notebook computers prone to catching fire, botched expansion efforts abroad.

FORBES: Magazine Article

Duran, the psychology student living in Mexico City, says Mexico's growing social media-fueled youth movement reminds him of the days he worked on phone banks for the 2008 Obama campaign.

CNN: Casting ballots on both sides of the U.S.-Mexico border

These days nostalgic baby boomers are bidding up prices of the stars of their youth, notably the Beatles.

FORBES: Starstruck speculators

She had been feeling envious for a long time of the higher life of the state, where there was now heroism, renown, and vigor, and where the youth and strength of an old woman, vainly expended in deprivation and horror in the old days, were in demand again.

NEWYORKER: Among Animals and Plants