As I was a Communications major back in the day, many of my friends are in the PR/Events/Press field. I get so many mass emails asking me to support X,Y and Z. Become a Facebook fan of ____ page. Join _____ Facebook group. Follow ____ on twitter. Emails to forward to friends. Etc, etc. etc.
EDIT: This is for purely work-related causes. Personal causes or volunteering positions are exempt.