I'm sure most of us have heard by now, but anyway:

http://blogs.zdnet.com/BTL/?p=7848&tag=nl.e539

Microsoft said Friday that it is making an unsolicited offer of $31 a share, or $44.6 billion, to buy Yahoo in a move that would give the software giant more market share and become a significant threat to Google.

In a statement, Microsoft would allow Yahoo shareholders to get cash or shares of Microsoft. At a 62 percent premium to Yahoo’s closing price of $19.18 the deal would seem like a no brainer for suffering Yahoo shareholders. Yahoo said it will evaluate the offer “carefully and promptly.”
$44.6 billion...