We have recently restarted an organization dedicated to discussion of underrepresented groups in physics and astronomy. The group discusses general issues in the field at large as well as within the department specifically.
Wine and Cheese
Modeled after the CAS Wine and Cheese seminars, these talks are organized as an opportunity for graduate students to give presentations in preparation for their Research Exam, GBO, and Thesis Defense.
Each incoming graduate student is paired up with a current student, and is encouraged to speak frequently with their mentor about the transition to graduate school.