I know what I am doing on the 4th...
 

Boomerang is offering up all 166 episodes of the Flintstones on the 4th of July. Sign me up and call me spanky, that sounds like a great way to spend the day! http://www.broadcastingcable.com/article/CA6456538.html

166 x 0.5 = 84 hours

Are they playing the episodes at 4x speed?

Any chance they're commercial free? That gets us down to 58.1 hours at 21 minutes per episode.

It will last over a couple of days. Though it would have been very cool to have it in 4x speed.