I've had the enormous pleasure of seeing Squarepusher a few times. The first time was at Glastonbury where the audience was surrounded by a four way speaker system. Squarepushers beats at 12am after a hard days partying were fantastic. I saw him at the Royal Festival Hall in London playing just solo bass guitar, it's unbelievable how good this guy can play, maybe one of the best bass players around.
He's been releasing music through Warp records since the mid-90's and if you haven't heard him yet you really should check him out, I'd rate him as one of the most influential musicians of recent times.
I'll leave you with one of my favourite Squarepusher tunes, and also one of his more 'accessible' tracks...