So why is exactly Night Crawler (from X-Men) blue?

I'm not one to tune in to every episode of any television show, or read every manga, or ever graphic novel, so I'm the fan with a lot of questions. And this is one of them. I never found out most of the background on Night Crawler, or Kurt? Isn't that his name-name? But an answer and possibly some details on his background would be much appreciated. Thank you for your time. Easy ten points!