Lisa: Rack

Last week, Mallory asked me if the expression was "rack your brain" or "wrack your brain," and I was forced to admit that I didn't know.

A ridiculously small amount of research turned up this excellent answer by Joann Hill at Random House. The whole thing is quite interesting if you like that kind of thing (which I do), but here's the relevant paragraph:

The word rack in racking (one's) brain is thus spelled. That is because it derives from the rack, the medieval instrument of torture on which a victim was slowly stretched. (This stems from the familiar rack 'a framework'.) This rack was used as a verb meaning 'to torture on the rack', and hence in the transferred sense 'to torture', and then figuratively 'to stretch or strain', which is the sense in rack (one's) brain.

Fortuitously, 'rack' is also my favorite euphemism for breasts.