2010 Threads of the year

I just came across a very interesting thread from earlier this year that I realised I'd completely missed. I realised that unless you read every single thread you may miss some real gems. As the year draws to a close I thought it would be both fun and beneficial to get the community to post their nominations for must-not-miss threads from this year under various categories.

Please provide a link to the threads you nominate. A little spiel on what makes that thread stand out would also be cool.

Finally, feel free to add your own categories here.