They handed them out at one of my previous jobs (corporate gig). Everyone that went for them came down with a mild flu after the shot and then proceeded to catch every other flu that came around during the winter.

edit: I hadn't realised sharing experience was such a downvotable offence... note I observed this over 3 years. Obviously the flu jab targets specific strains of flu, if the jab you get doesn't target the strains that happen to come round that winter then it's not going to help at all. I've no idea how well they can predict which strains will be in circulation but in my experience, not very well.