Technical explanations

[Ric_]

My ultimate favourite is to let the phone ring a few times, then pick it up and say something like "hello, maths.."..more often than not, people hang up...

 

This works especially well if you have somebody from that department in your office at the time - e.g. maths rings you so you get a maths teacher to answer

 

... it's the simple things in life!

[Sirbendy]

Another one I forgot, that I got the chance to use this morning...

 

"I'm sorry, but the systems have gone up their own arse again..".