1. A computing system configured to manage execution of programs for users, the system comprising: an interactive request manager component that is configured to manage execution of programs for users of a program execution service (PES), the interactive request manager component comprising physical computing hardware configured to: receive a request from a first user to share, with users of the PES, a first virtualization environment generated for the first user, the first virtualization environment including an operating system and at least one program service provided by the PES, the program services comprising a user-customizable load balancer configured to allow a user to distribute workload across one or more of the plurality of computing nodes or one or more instances of the virtualization environment for a user application; update a list of virtualization environments available for selection by users of the PES to provide an updated list of virtualization environments that includes information related to the first virtualization environment; provide the updated list of virtualization environments to users of the PES; receive a selection of the first virtualization environment that is included in the updated list from a second user of the PES; and generate a second virtualization environment for the second user, the second virtualization environment based at least in part on the first virtualization environment.