The watershed is the time limit after which more controversial subjects, bad language, etc, can be shown on TV in some countries, so if it's after the watershed, then discussions can be freer, franker and more controversial.
Similar to ahead of the pack, ahead of the curve literally refers to your position on the statistical bell curve, where the top of the curve represents the median, average result. By being ahead of the curve you represent the top percentile of results that either has the advanced skills or understanding that sets you apart.
(UK) An idiom that appears to have gone out of use but was prevalent in the English north Midlands of Staffordshire, Cheshire and Derbyshire from at least the turn of the 20th century until the early 1950s or so. The idiom's meaning is literally something said or written that is unbelievable, rumor, over embellished, the result of malicious village gossip etc.
(USA) If you have been all over Hell's half acre, you have been traveling and visiting many more places than originally intended, usually because you were unsuccessful in finding what you were looking for.
It can also be used to mean everywhere.