How to create cloudwatch event using cloudformation template?

I am pretty sure the CloudWatch Event is yet to be exposed via the CloudFormation API. There is normally some lag between new features in AWS and them being implemented/exposed by the CloudFormation team.

Here is the list of resources currently available via CloudFormation. http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-template-resource-type-ref.html

As one can see there is only one resource in the Cloudwatch namespace.

Adding CloudWatch event rules and schedules in now available, see https://aws.amazon.com/about-aws/whats-new/2016/04/amazon-cloudwatch-events-now-supported-in-aws-cloudformation-templates/