There are two main ways I've personally contributed to the math community, and many interventions and opportunities that I've observed- this page covers both.
How I've helped
At UIC I and my friend Ellie Dannenberg founded the annual Midwest Women in Mathematics Symposium, which was held at UIC in 2013, Notre Dame in 2014, Dominican in 2015, UIUC in 2016, IUPUI in 2017 and will be held at Purdue in 2018. The day-long symposium includes talks, research meetings, networking, and breakout sessions, and is based entirely off of the Southern California version that I attended in 2012, now called WIMSoCal. Along with my friends Michelle Chu and Hannah Turner, I founded another conference, the annual Texas Women in Mathematics Symposium, in 2016. It was supposed to be held at Lamar University in 2017, but due to flooding from Hurricane Harvey it will be held at Sam Houston State University. Finally, at UNCC I organized a Carolinas version of the same event, which will be held at Campbell University next year.
Here is the not-fancy list of opportunities I know about for women/underrepresented groups in mathematics. Please contact me if you'd like me to add more conferences/fellowships/workshops/opportunities to it.
How You can Help
I've been around three different graduate schools, and they've all done great things to support women. The weekly-ish Hypatian seminar at UCSB is ridiculously valuable and special- if you're interested in making students from underrepresented groups feel supported, check out the history section of the seminar for ideas on what you can do at your school. For instance, panels from advanced grad students on how to do research/find an advisor/give a talk/teach, roundtable discussions, and cross-disciplinary speakers re: teaching, mental health, etc. While at UCSB I started the now-defunct M&M seminar, which was held in the Philosophy department and discussed papers in math and philosophy with undergraduates, graduate students, postdocs, and faculty.
At UT Austin I've been able to attend the incredible Distinguished Women in Mathematics Lecture series which invites women professors to UT to give math talks and have lunch with the women graduate students. These lunches have been very eye-opening and are a great way for the women of the department to get together. UT Austin is also where Math Girl Margarita Night started, which I also went to at UCSB. If you have no funding and almost no time, hosting informal potluck brunches is a great way to support your community- we started that at UIC, inspired by a friend who did them at U Chicago. Another is to form a mentorship program- I've seen several between grad students, and I've mentored a few undergraduates through the Direct Reading Program at UT.
Personally I think raising awareness and giving credit are two great ways to support your community, which is something I'm trying to do with this page. Top picture is of me being the Distinguished Graduate Speaker at USTARS, a conference co-founded by the picture taker Dr. Erik Insko. Bottom picture is from that UIC newsletter article, and is, from left to right, Ellie Dannenberg , Janet Page , Jessica Dyer , me, and Cara Mullen . This page is inspired by Lillian Pierce's website