Two guys, Stan and Ed, were working a construction job digging a ditch.

Two guys, Stan and Ed, were working a construction job digging a
ditch. The foreman was at them all the time to keep busy. No breaks, just work,
work, work! Finally it dawned on the two guys that the foreman left every day
at 3:00 in the afternoon. So they decided to start leaving at 3:15.
The very next day when the foreman left at 3:00, Stan and Ed left at 3:15.
Stan goes home, walks through the house, opens the bedroom door, and there
on the bed is his wife and the foreman. Stan quickly runs back to the job and
digs like mad until 5:00. The next day when Ed arrives at work, Stan says,
"Listen Ed, we can't knock off work any more at 3:15... I almost got caught!"