100 O'Clock 

too late or too long

We didn't get home from that party until 100 O'Clock.

It already feels like 100 O'Clock.

This conference lasts until 100 O'Clock.

100 O'Clock by smartypants2011 June 11, 2011

100 'o' Clock 

When it is so late and your mind is gone, and you just don't care what time it is anymore.

"Dude I'm so wasted, what time is it?"
"I don't know, 100 'o' Clock."

100 'o' Clock by NoWayDude December 9, 2008