"The Text Retrieval Conference (TREC) workshop (call for participation) series encourages research in information retrieval and related applications by providing a large test collection, uniform scoring procedures, and a forum for organizations interested in comparing their results. Now in its fifteenth year, the conference has become the major experimental effort in the field. Participants in the previous TREC conferences have examined a wide variety of retrieval techniques and retrieval environments, including cross-language retrieval, retrieval of web documents, multimedia retrieval, and question answering. Details about TREC can be found at the TREC web site, http://trec.nist.gov. [...]

By May 2006 -- submit application described below to NIST.
Returning an application will add you to the active participants' mailing list. On Feb 27, NIST will announce a new password for the "active participants" portion of the TREC web site. Included in this portion of the web site is information regarding the permission forms needed to obtain the TREC document disks. [...]

August 1 (estimated)
results submission deadline for many tracks (Results deadline may need to be earlier or later for some tracks depending on assessor availability. Specific deadlines for each track will be included in the track guidelines, which should be finalized by May.) [...]" (Chamada completa)