Mine came about through work nicknames..... due to me sporting a full beard when I started out on my first 'proper' job as a trainee mechanic 13 or so years ago.... The other techs adorned me with the title 'Beard', often spoken in a variety of amusing tones. The insanity part came about partly through my own assessment of my sometimes mental state, but maybe also because of 'Lord insanity Melchett' (played by Stephen Fry) as he was referred to by the title character of Blackadder (not sure how well Blackadder is known outside of the UK). Can't remember how it happened but a fellow mechanic and friend at the garage put the insanity and beard together, thus it was born!
As for the avatar, it is a picture of my mascot (cue mass ridicule) 'Mr Cheery Chick' as he is known, an amusing roly-poly soft toy picked up for next to nothing one easter in a supermarket.... viewed from some angles, he seems to have a personality and life like quality all of his own....
I'll shut up now... Oh crap, gotta go, it looks like an Arkham Asylum van just pulled up outside the door....