This module allows students to enrol themselves in a group within a course. The teacher can select from which groups the students can chose, and the maximum nummber of students allowed in each group.
The students can view the members of each group before making a choice, and (if the teacher allows it) change their selected group until the deadline.
This module is heavily based on the "choice" activity module, and behaves roughly like it. Making a choice enrols you in a group, changing your choice unenrols you from the precedent group and enrols you in the new one, and so on.
Here is a screencast made by Mary Cooch that goes in more detail as how the module works :
This will be used as a replacement of the ugly hack we presently use in Moodle 1.9 (see http://moodle.org/mod/forum/discuss.php?d=105497), when we switch to Moodle 2.0.
Comments, bug reports, etc. are welcome.