Brainstorming is a group creativity technique that was designed to generate a large number of ideas for the solution of a problem. The method originated in a 1953 book called Applied Imagination by Alex Faickney Osborn, an advertising executive. Osborn proposed that groups could double their creative output by using the method of brainstorming ...
Although traditional brainstorming may not increase the productivity of groups, it has other potential benefits, such as enhancing the enjoyment of group work and improving morale. It may also serve as a useful exercise for team building.
(source: http://en.wikipedia.org/wiki/Brainstorming)

The term Classical Brainstorming is often used to describe traditional brainstorming

Brainwriting is a variation of brainstorming where ideas are written down by individuals, and buzz groups.

Creativity techniques are the terms given to a wide range of techniques or methods which can be used with individuals or in team situations to facilitate a systematic approach to turning explicit individual experiences, knowledge and creative ideas (stored in peoples' brains) into a format which can be transferred to others and used to create new knowledge and to find innovative solutions".
(source: http://en.wikipedia.org/wiki/Creativity_technique)