There is an exact translation for "How about" in German which would be "Was hälst Du von.. ?/Was hälst Du davon?" but it is rarely used and not nearly as often as how about. So I'll give you some alternatives and most of the time you don't need to translate how about. Hast Du Lust ins Kino zu gehen? (Was hälst du davon, ins Kino zu gehen? also possible here) Lass uns nochmal in der Mitte des Liedes anfangen! (Was hälst du davon, nochmal in der Mitte des Liedes anzufangen?) Das ist ein toller Film. Worum geht es? Ich hasse diesen Film. Was daran magst Du nicht? (:

'How about .." could also be expressed as : Wie wäre es (mit )....? Wie wäre es ,wenn wir ihn anrufen würden ? How about calling him ? Wie wäre es damit ? How about it ? As for "what about " in the context of the examples you gave and that Fab gave a great translation of , that is not the 'what about ' to compare with ' how about ' . 'what about 'could have almost the same meaning of 'how about ' with a slight difference in connotation . When you say 'how about ' you are offering a suggestion ,that you find favorable from your point of view , while ' what about ' is used to express the concern about a matter as an objection of the before mentioned statement . "How about we go to the cinema ?" Wie wäre es mit .... ( here it is a suggestion ) - Sure I would like , but what about the unfinished work we have to do ? " Was ist mit ... ? ( here it is a concern contradicting with the before mentioned ) .