There are six types of events that you can create in sharepoint 2010. These are :

List Events -
Adding/ed a new list field.
Updating/ed a field.

List Item Events -
Adding/ed a new list item or document.
Document checking/ed in or out.
Adding/ed an attachment.
Deleting/ed an item or document.

List Email Events -
A list received an email.

Web Events -
Deleting/ed a site collection or site.
Creating/ed a new site collection or sub site.

Feature Events -
Feature activating/ed or deactivating/ed.

List Workflow Events -
A workflow is starting/ed, postponed, or completed.

For complete example see