Marketo allows you to create entries directly in your Marketing Calendar by using the program focus mode. You can create the following entry types:
Go to the Calendar.
Select a previous entry and click Show Program Focus.
Once in program focus mode, select the day of your choice to add an entry.
Name your entry and select a type.
Notice you can also create Smart Campaigns, Email Programs and Basic Entries in this same manner.
When done editing, close program focus mode.