What are the Complex Plugin & Custom Workflows Sceniaros

Hi Aao all,

    I am fresher to dynamics CRM and in learning stage of plugin and custom workflow development in dynamic crm 2013. I have created simple plugins of Pre, Post, Pre Image, Post Image on create, update, delete on an entity. But I think these are not enough to fully understand these topics until to implement some scenarios.

Can anybody suggest me some complex Plugin and Custom Workflow scenarios that should I try before moving to next topic.

Any type of suggestions will be appreciated.