ß
An esset is a German Language character that is commonly used as a double 'S' pair ('ss'), though in a pinch any german speaker will recognise 'ss' to be 'ß'. Although is resembles a capital 'B' to speakers of many other languages, pronuncing it as a 'b' will just sound silly.
Examples of words using an 'esset' are:
North-america keyboards are not usually set up to handle these special characters, but thay can be done. Under Windows with the US Internation Layout you can (usually) do it by holding down the ALT key and typing '0223' on the numeric keypad. Many linux users can also do it by hitting 'Shift+Meta', then the accent operator to be used and then the letter to apply it to; so to produce an esset I would hit shift+meta, then 's' follwed by 's' again to produce "ß".
Note: It has come to my attention that this is not the only name for the character "ß"; it appears that it is also sometimes spelled "eszet", though from my experience, "Esset"/"Eßet" is the most common.