From phpBB Development Wiki
Rich Text Editor Integration
Expected results: Integration of a Rich Text Editor into phpBB core, making the use of the bulletin board a lot easier by allowing users to pick the editor that fits their needs.
Session Backend Abstraction
Brief explanation: High traffic websites can already make use of fast in-memory stores (such as memcached or Redis) for improved caching. However volatile session data is still handled by the (relational) database, occasionally causing load problems. First very complete test coverage of current session code should be achieved to be able to guarantee the continued correct functionality of the session mechanism, which is of critical importance to running a board. The session code should then be refactored to provide an abstraction of the storage mechanism used, to allow for faster backends to be implemented.
Expected results: A properly designed storage interface for session data and working backend implementations for relational databases and memcached. A Redis implementation would be useful but is optional.
Knowledge Prerequisite: Object-oriented PHP required, familiarity with key-value stores useful but not mandatory.