Lately I have been playing a bit with F#, mainly out of curiosity. To be honest, functional programming looks a bit scary to me, especially the syntax. But the guys over at fsharp.org and fsharpforfunandprofit.com are pretty persuasive, so I did decide to invest a bit more time in playing with it. I will see where it will lead me. Hopefully I'll blog something concrete about #fsharp in a little while.
As a part of my journey so far I stumbled upon this video where Jessica Kerr explains the basics of functional principles and how to apply them in our "main" languages, like Java or C#. I strongly suggest you invest a bit of time and at least take a look at what it's about and how you can apply functional principles already today.
I really, really think you can watch the video and take away something from it immediately. It might even inspire you to try a bit of functional programming yourself.
Jessica also has a blog and she also tweets under @jessitron. I suggest you pay her a visit.