Many small and medium size research groups have limitations to execute their HPC workloads because of the need to buy, configure and maintain their own cluster or grid solutions. At the same time, some research groups have large infrastructures with low utilization levels due in part to the tools they offer to end users, that require that each end user configures complex and distributed environments. In this paper we present an effort between a private and public institution to offer scientific applications as a service taking advantage of an existing infrastructure to create a private IaaS using OpenStack, and offering scientific applications through a friendly user interface. This strategy facilitates that researchers can run their HPC workloads on a private cloud in a transparent way, hiding the complexities of distributed and scalable cloud environments. We show how this strategy may help to increase the utilization of infrastructures, how it allows end users to easily execute and share their applications through a SaaS marketplace, and how new applications can be configured and deployed using a PaaS platform.