jonathon

Pronounced JON-uh-THON.

An extraordinarily lengthy period of absence from work. So much so that it requires regular dedicated training.

Can also refer to the training itself.

Person a: "Looks like he's doing a jonathon."

Person b: "Nah, he's only had 6 separate periods of absence this quarter. Looks like he's training for a half jonathon."