Hit for six

"Hit for six" was a cricketing expression. It indicated a ball which had been hit over the boundary line without bouncing on the ground first. Such balls won their batsmen six runs. Ishtar Hutchings nearly "hit for six" to conclude the 2010 match between the Doctor's Invitation Eleven and the Cheldon Bonniface Invitation Eleven, but Sanki caught it before it could sail over the boundary. (NA: Happy Endings)

Behind the scenes
The term has seeped into the wider British culture, in which it's usually used (e.g., from the ball's perspective, as in, "to be hit for six") to mean some devastating action which has been visited upon the subject of a sentence. For instance, if one says, "I was hit for six by her beauty", one means that you were completely blown away by how beautiful she was.