Cloud computing systems have emerged as a type of distributed systems in which a multitude of interconnected machines are gathered and recruited over the internet to help solve a computation or data-intensive problem. There are large numbers of cases in which Cloud techniques solely are not able to solve the job due to the nature of the tasks. To overcome this problem recently a strong inclination has emerged towards enlisting the human intelligence and wisdom of crowds a.k.a. Crowdsourcing in combination with the machine automated techniques. In this paper the authors propose a model for integrating crowds of people in the Cloud environments to enrich Cloud computing environments to be able to provide hybrid human-machine services enabling it to solve a wider variety of problems which some of them are studied here. The authors nickname these rich types of services, Crowd-enhanced Cloud services. At the end, the modality and challenges of this convergence and its future trends are explored.