Well... everyone wish me luck with the big lottery tonight. I told my wife that if we win, I'm giving $10 million to the React OS guys (she looked at me like I was from Mars). Maybe even more if it looked like they would actually finish the thing.
I would even fund an open source replacement for Outlook. For us, that's the one app I would have huge problems with prying from people's hands. I think it's the case for most enterprises. I could replace Word/Excel with Open Office or Libre Office, but Outlook is where I would get the most resistance.