The Drug Policy Alliance (I’m a member) is promoting contact with members of Congress to promote legislation to decriminalize medical marijuana. Letters matter. I suggest visiting the DPA letter-writing page, but then also writing your own letter from your own email address, as they’re more likely to be counted. Here’s the page for writing personal notes to your representative in the House; here’s a page for your Senators (it will require a bit more navigation after you get to the pages of your Senators).