Volunteers for Salesforce (V4S) helps organizations manage volunteer events and people. From managing volunteers, jobs, shifts, and hours, this product allows nonprofits to track and report on all of the data as well as allow public signups on a website. It come pre-installed with NPSP, or you can download it for free from the App Exchange.
The Coalition for Home Repair doesn’t currently have many volunteers to manage, but may consider using this app in the future.