Overheard in the computer lab

I was tappity tap tapping away in one of the computer labs, when a colleague came in to take the next class, with several students in tow.

Colleague:

(in raised voice)
"There is now a practical class going on this lab. Everyone log off please, to let this load of oiks in to log on."

(turning to students trailing in behind)
"Load of oiks: has everyone got a practical sheet?"