6:00 PM -- Cisco Systems Inc. (Nasdaq: CSCO) disclosed today that it's selling $4 billion in debt, a move that has people speculating about a big acquisition to come.

Half a billion of the money goes to paying off older debt, but that still leaves a few billion to play with. Cisco has $29 billion in cash and investments, but less than $4 billion is in the United States, as noted by Reuters.

So, it might be just a way to shore up cash in tough times, to appease investors. Or, it could be a way to quickly gather cash for a deal, which is more fun to think about.

Let the speculation begin. It has to be big -- more than a few billion dollars. Probably peripheral to Cisco's main businesses, so, not Brocade Communications Systems Inc. (Nasdaq: BRCD).

I'm thinking it would be in the consumer space. CEO John Chambers has said out loud that Cisco would consider consumer acquisitions and noted on the last earning call that he's given senior VP Ned Hooper the OK to expand that business. (See Cisco Goes Consumer and Cisco Keeps the Service Provider Faith.)

I have no good guesses. I have bad guesses that I won't say here for fear of starting a dumb unintentional rumor. (Although -- isn't Twitter Inc. worth like $100 gazillion right now, according to Web 2.0 pundits?)

You, though, don't have to care about that. Take your best shot on the message board below.

— Craig Matsumoto, West Coast Editor, Light Reading