RIPE is the acronym for Reseaux IP Europeens and represents the RIR for Europe, Middle East and Central Asia.
It is important to keep in mind that RIPE is not an institution like IETF, but rather an open forum for all members and non-members which may have an interest in the technical development of the Internet. In the same way, RIPE is not a legal entity and there is no formal membership required or imposed. 
The main focus and interest of RIPE is the Internet's technical development for the region it represents.
When referring to the RIPE community, there is no distinction between RIPE members or RIPE NCC members. Anyone who has an interest in the way the Internet is being managed or governed is considered as part of the RIPE community.
All started in 1989 at Amsterdam when a group of IT network operators decided to start organizing meetings to share knowledge and experiences related to their work. At first there were 14 representatives from 6 countries which were part of 11 networks.
RIPE became an organization in November 29 year 1989. More and more IT network operators joined the RIPE meetings and there was a need for a coordination center. A year later, in September 16 year 1990 RIPE NCC was also established for administration tasks. Only in 1992 RIPE NCC was formally established and recognized. 
RIPE vs RIPE NCC
RIPE is not the same thing with RIPE NCC. Their functions, attributions and tasks are different. In this was, according to the official RIPE website, "the RIPE NCC (Reseaux IP Europeens Network Coordination Centre) is one of five Regional Internet Registries (RIRs) providing Internet resource allocations, registration services and coordination activities that support the operation of the Internet globally." 
In this way, the RIPE NCC supports RIPE by facilitating the meeting of this RIR and even providing support for the RIPE working groups. RIPE NNC maintains the RIPE database by creating and managing a document store. RIPE NCC was formally established in 1992 by RIPE. Starting with 1998. RIPE NCC became a legal entity of its own , but these organizations continue to cooperate as before.
RIPE working groups
In order to deal with issues and develop new policies, RIPE organized various working groups based on the number of issues studied. These issues can be proposed by RIPE members and influence RIPE NCC members and the whole Internet community. The volunteers which are part of these working groups maintain communication and discussions by means of mailing lists. However, there are two meeting on a yearly basis as RIPE meetings and sessions.