None of the default Interesting Moment Types (Web, Milestone, Email) fit the description I would like. It's not immediately clear how to create my own interesting moment type for Marketo Sales Insight.
You can simply type in what you would like the type of the Interesting Moment to be instead of choosing one of the options in the drop down. See the below screenshot:
Who This Solution Applies To
Salesforce Sync, Sales Insight Users