Here's a few service groups throughout Detroit:
The Detroit Mower Gang
Started by Tom Nardone this group cares for parks throughout the city. Started after funding was going to allow the parks to become unusable this group mows, cleans, and repairs city parks.
Reclaim Detroit
Reclaim Detroit is an organization that helps demolish abandoned buildings in a unique way. Volunteers take the buldings a part piece by piece, saving what can be reused for new construction.
Arise Detroit
Arise Detroit is all about having communities come together to make Detroit a better place. Arise started the yearly Neighborhood Days, which encourage people to plan projects with their friends and neighbors.
Volunteer Impact
http://www.volunteerimpact.org/
Volunteer Impact is a larger group that connects people with volunteer jobs they have experience in. Areas include guidance counseling for highschoolers, hospice assistants, food delivery drivers, and many more.
Neighborhood Service Organization
http://www.nso-mi.org/index.php
The NSO seeks to provide programs for the people who need it most, the homeless, elderly, and disabled. It is part of a service network that can connect people with the help that they need.
EACH
EACH is a collaboration between churches in Detroit and the suburbs. There are a variety of different programs going on, from mobile medical clinics, to service projects, to food distirubution.