I've been banging my head on the desk all morning trying to do this, and before I decide there isn't a way, please let me know if I just missed something painfully obvious. Our organization sells classes as our opportunities. In our opportunity section, we have a custom formula field, "Training_Address_Info" which fills in the field from info in the account related to the opportunity. Once the opportunity - the class - is sold, we have to schedule an instructor for it, so we create an event for the instructor, which is related to the opportunity. I'm trying to create a custom activity forumla field which will pick up the "Training_Address_Info" field from that opportunity. There are actually a few fields I'd like to reference from the related opportunity, but there doesn't seem to be a way to create that relationship between the event and opportunity - but I'm still learning lots regularly, so maybe I just haven't figured it out yet? (Apologies for any awkward wording, I'm also still trying to master the lingo!)