Do you mean accessing the event object from within the event box ?
The structure of the event div is as follows:
<div> <-- this is the main event div
<div>
e.InnerHTML
</div>
</div>
If you render your code in BeforeEventRender event you can reach the event object using the following code:
e.InnerHTML += "<input type='button'" +
"onclick='dp.eventMenuClickCallBack(parentNode.parentNode.event, 'Delete');' +
"value='Delete' />";
This code adds a button that calls a custom callback action (it executes EventMenuClick event on the server-side, passing "Delete" as e.Command value).