THE DIFFERENCE BETWEEN XV
Credit: Butler Webs 

The difference between then and now for Baby Boomers:

Then: Long hair
Now: Longing for hair

Then: KEG
Now: EKG

Then: Acid rock
Now: Acid reflux

Then: PAAR
Now: AARP

Then: Hip joints
Now: Hip replacements

Note: Jack Paar was the original host of The Tonight Show - before Johnny Carson.