We have done following different kinds of integration with Salesforce:
We have worked on API callouts to send single and bulk message to sms web service which in turn send SMS to specified phone number. This API is called depending upon the value of one field that gets updated dynamically.
We have also created tasks that keeps a track of next message to send.
Integrated Zendesk system with Salesforce (Two way sync).
Whenever any case is created and matched to certain criteria, create new Ticket in zendesk with Case comment as Ticket comment and keep both records in sync after creation.
One of our clients wants to pull Salesforce Knowledge Articles into their Contentful system.
We have implemented a scheduler to aggregate the new and revised article content and then open an API connection and upsert the content using the Internal Article ID value.
We have integrated ExactTarget with Salesforce. Triggered email definitions in Exacttarget org (Salesforce marketing cloud), to send emails via email templates.
We have created a visualforce page to select an email template from salesforce to trigger an email to send to the Lead record (Salesforce) from Exacttarget org.