busman's holiday

A vacation during which one engages in activity that is similar to one's usual work.

(BUS-manz HOL-i-day)
noun

A holiday spent doing things as at work.

[Imagine a bus driver having a day off, 'enjoying' a bus ride and you'll have a pretty good idea of this term. Going on a long drive might be a great vacation for many of us, but not for a bus driver. Of course, when the phrase came up some 200 years ago, bus drivers had charge of horse-drawn buses. The term is sometimes seen as 'businessman's holiday'.]

Usage:

"Boundless energy and vaulting ambition carried Nicolas Sarkozy to the presidency of France. Now that he has had just over 100 days in office (including a hyperactive busman's holiday in New Hampshire), it is a good time to take stock of where all this energy may be leading." — The World According to Sarkozy; The Economist (London, UK); Aug 30, 2007.

Free time spent in much the same pursuit as one's work. For example, Weather permitting, the lifeguard spent all her days off at the beach--a real busman's holiday. The term alludes to a bus driver spending his day off taking a long bus ride. [Late 1800s]

The noun has one meaning:

Meaning #1: a holiday where you do the same things you do at work