This month I've been playing the Minimalism Game care of The Minimalists (http://www.theminimalists.com/minsgame/). Basically you need to remove items from your home each day for the entire month. On the first day you get rid of one item, the second two, the third three etc until, by the end of a 30 day month you have removed 465 items from your life.
At the start of the month I thought this was going to be hard as I had got rid of a heap of stuff when I moved premises less than a year ago and I hardly fit the stereotype of a hoarder (except for shirts and designer chairs!). It certainly took time and mental effort but it wasn't hard finding 465 items that I didn't use or need in my life. In fact I think I could continue the game through July too!
I found the best thing about The Minimalism game is that it has got my brain engaged to look for things I do not need rather than overlook them. I highly recommend giving it go.