Transfer tennis
I once worked in a small office - about 6 of us in a large studio. We had a game - Transfer Tennis. Easy to play. You transfer the call to the next person - +1 point. Each time you get it back, you increase your points gained, eg, second time, +2; third, +3. If you get hung up on, thats -5. Each swear word from the caller is +1 (must be on speakerphone to get this) and +5 for death threats.
It would go like this:
<ring>
Me: Good morning this is blah blah blah, etc...
India: Yes very good morning to you too sir we have detected a fault with your...
Me: Ah, is this IT related? I'll transfer you to IT.
2nd Player: Hello, etc (longer and more complex greetings are good form)
India: Yes it is a very fine morning indeed sir could I just get you to turn on...
2nd Player: Ah, you're after IT? Sorry, this is finance, we use abacusses. I'll pass you to IT...
etc. When it gets back to you, you could try a silly voice (Indian accent: Oh, hello? You are being transferred too? What a coincidence! Please hold!) or just use the same voice, pretend to be a different division - if challenged, say 'Oh you must mean Roger, he sounds just like me.'
Scores in the teens are considered legendary and you will receive fame and your colleagues ovation forever.