Mike Schinkel, president of Xtras.Net, made an offer on his personal blog of a free XDN Professional membership (http://www.xtras.net/xdn) during the month of May 2004 for anyone that blogs about .NET frequently.
It's a bit late now, but if you are a .NET blogger, see Mike's post for how to get your free XDN membership.
I must say, quite generous of him.