The imperial pint is a unit of volume in the imperial unit system with the symbol pt.
1 imperial pint is equal to 1/8 of an imperial gallon. This is equal to 1/2 imperial quart, 4 imperial gills or 20 imperial fluid ounces. In SI / metric this equates to 568.26125 ml.
In Britain, all beer, ales and stout must be served in pubs by the pint (or half pint). Every single glass, despite being a 'pint' must have the numbers 568 ml printed on the side - and because of this, is likely the most commonly known conversion factor amongst the British population.
The acre-foot is a unit of volume in the US customary unit system with the symbol ac⋅ft.
It represents the volume contained in a box measuring 660 feet long, 66 feet wide and 1 foot deep. This can be thought of a box the size of an acre but 1 foot deep.
It is approximately the same volume as an 8 lane swimming pool; 25 metres in length, 3 metres deep and 16 metres wide (assuming lanes are 2 metres wide).
It is still used in the US despite its links to the much-outdated imperial system of units. For example a "rule of thumb" is that an average suburban family's annual water usage should be around 1 acre-foot. This is equal to just under 3.4 m³ daily.