Here are a few prank phone calls using the voice of Arnold Schwarzenwhatever that I found at StupidCollege.com and EbaumsWorld.com.
And don't worry, their safe to listen to at work...just not too loud.
Arnold Calls Hooters
Arnold Calls Gateway
Arnold Calls Someone's Mother
Arnold Pizza Answering Machine...with laughing idiot
Arnold Calls Motel
Arnold Calls Reality
Arnold Deals with Telemarketer