Sharpening

I've been thinking a lot about the people I surround myself with and how that affects me.  I had a meeting with my buddy Tim Deering yesterday and he challenged me further in my thinking, he said, "The people you spend quality time with affect your motivation and can bring you down or lift you up."  (I'm sure I didn't capture the quote perfectly.)  Essentially, his question was, who are you spending quality time with that encourage and challenge you?

My answer, "no one, really".  Obviously I spend time with Tim on a regular basis and he feeds life into me but who am I challenging and being really challenged by?

Seth Godin had a great post today on his blog, Who is making you Uncomfortable? And he brings up a great idea about how we should surround our selves with a couple of very close people who can call us out and make us better.

So, I am looking for ways to implement these types of relationships in my life.  What are you doing about this?  How did you go about surrounding yourself with these people?