This is my favourite mass building routine for bi's, a variation of the pof idea where I hit them from all 3 angles.
standing barbell curls 3 sets 5-6 reps
incline dumbell curls 3 sets 6-8 reps
strict preacher curls 2-3 sets 8-10 reps with a drop set at the end
I find this program always seems to pack mass on my bi's, but when I'm specializing on arms, I'll do a fast and light workout for bi's on back day, tri's on chest day, but also have a separate arm day where I go really heavy and hit them on their own.