1 MBE represents 0.5 liter (17 U.S. fl oz) with 5% alcoholic content (one pint basically).
Thus your average Jack Daniels bottle (1 litre) relates to 16 MBE.
The units name is derived form the label of the notorious Augustiner Helles (featuring a monk thus "man") which serves as a benchmark for this chart.
As indicated above it can be applied on any sort of alcoholic beverage but serves best to count your beer consumption when clubbing and gives you an impression at what point you are as well as a handy reference the next day.
It is strongly recommended to benchmark your peak in order not to end up in the gutter vomiting your f**king shit out.
Guy2: I guess we´ve had both like.. dunno 10 MBE or sumthin...
Guy1: WTF?? How did that happen?
Guy2: Dont ask me i cant remember anything past 7 MBE...