Found this shit on /qa/ and it seemed interesting, so let's make some god damn pixel art!
Step 1. Download Pixelator here: http://pixelatorapp.com/download.html
Step 2. Apply for a personal (free) license to remove the watermark here: http://pixelatorapp.com/buy_license_personal.html
Step 3. Load up an image and fiddle around with options until you get something good!