Houston has a heart as big as the Lone Star State.

It's true that philanthropy circles donate cash by the millions at fancy fundraisers and dress-to-kill galas, but the essence of giving is also evident in the time Houstonians devote to help their fellow man. Consider the Houston Livestock Show and Rodeo and the Texas Medical Center for example, two local institutions that thrive and survive because of the participants who give up their time for good.

The standard measure that assesses the economic impact of volunteering assigns a dollar value to the amount of time put in by residents every year.

"A very conservative projection for volunteering in greater Houston during 2011 puts the dollar value at over $2.4 billion dollars," Volunteer Houston executive director Mabel Menefee says. "Many small organizations would cease to exist without the support of volunteers."

Volunteer roles are as diverse as those found in employment, Menefee says. There are volunteer medical personnel — which includes fully credentialed doctors, nurses and lab technicians, as well as uncredentialed support staff — volunteer attorneys, office assistants, IT professionals, counselors, airplane pilots, accountants, physical laborors, entertainers and on and on.

And there're also youth, senior citizens, people of all age brackets, ethnicities and socioeconomic backgrounds who carve part of their day to lend a helping hand, whether that's because they are concerned about a particular cause, yearn to make a difference, want to sharpen their job skills or broaden their social network.

This holiday season, we are encouraging Houstonians to pencil in giving back in their shopping list. If you don't know how to get started, organizations like Volunteer Houston can help match your expertise with available opportunities.

With the help of Volunteer Houston, we've put together a list of good-doing organizations that are looking for your time to bring holiday cheer to those who need it most. If we've missed your favorite volunteer activity, feel free to share it in the comments.

The Salvation Army

The Salvation Army needs help in the Secret Santa Warehouse, its giant toy shop, to sort and wrap gifts for at-risk youth and seniors. Volunteer shifts are Monday through Friday, 9 a.m.-1 p.m. or 1-5 p.m., now through Dec. 31. Refreshments are provided. Ages 16 and up.

Location: 1500 Austin Ave, Houston, TX 77002
Contact: Monica Santillan, 832-201-8018, santillan@uss.salvationarmy.org.

Houston Food Bank

Houstonians love to eat, though too many go hungry everyday. The Houston Food Bank always needs volunteers to sort and package items for delivery to partner kitchens and service organizations. Go on your own or get a group together. The more the merrier.

Location: 535 Portwall, Houston, TX 77029
Contact: Anya Angermeier, 713-547-8534, aangermeier@houstonfoodbank.org.

Child Advocates

On Dec. 12, Child Advocates clears out its Santa's Warehouse. The nonprofit is on a mission to find able bodies to help move boxes and organize the many toys donated for children who need a bright holiday season.

Location: Call for information.
Contact: Kelly Goff, 713-529-1396 ext. 214, kelly.goff@childadvocates.org.

Fort Bend Women's Center

If you are a neat freak, the Fort Bend Women's Center is looking for you. The Santa Store is seeking individuals to organize, run and collect donations from clients and their families and assist patrons with their shopping. Volunteers are needed on Dec. 14 (1-5 p.m.), Dec. 17 (9 a.m.-noon, 1-4 p.m. and 4-7 p.m.) and Dec. 18 (9 a.m.-noon, noon to 3 p.m., 3-6 p.m.).

Location: 2012 Avenue G, Rosenberg, TX 77471
Contact: Patty Holt at pholt@fortbendwomenscenter.org.

Harris County Children's Protective Services

The BEARing Gifts Toy Drive needs help matching donated gifts to children's wish lists, distributing such gifts and cleanup. Shifts are through Dec. 20, 9 a.m.-noon and 1-4 p.m., with some evening work available for organized groups of 10 or more.

Contact: Michelle Searles, 713-295-2794, michelle.searles@dfps.state.tx.us.

Harris County Psychiatric Center

Men and women's pants, jackets and shoes without heels are needed for the 225 adult patients, 26 teens and 8 young children housed at the Harris County Psychiatric Center. Though holiday gifts, toiletries and games are also welcome.

Contact: Carol Rone, 713-741-8692, carol.j.rone@uth.tmc.edu.

Neighborhood Centers

Part of the Head Start/Early Head Start venture, the Adopt a Family initiative is looking for volunteers to read stories submitted by families as well as helpers to initiate a personalized clothing, food and toy drive. Donations can be delivered by a service worker or yourself.

Location: 6200 Savoy St., Suite 1100, Houston, TX 77036
Contact: Nelsy Martinez, 713-273-3227, nmartinez@neighborhood-centers.org.

Galveston County Animal Resource Center

Many regular volunteers of the Galveston County Animal Resource Center travel for the holidays. You can care for stray, unwanted animals and help owners reunite with their lost pets by listening to descriptions and checking the animals at the shelter. If you have room for pets, consider becoming a foster parent.

Location: 3412 Loop 197, Texas City, TX 77590
Contact: Gwen Norman, 409-948-2485, gnorman@gchd.org.

City Wide Club of Clubs

Be a part of a team that helps 45,000 people receive a meal on Christmas Eve. You can set up, serve food, distribute canned goods and clean up. Shifts are anytime between 7 a.m. and 6 p.m. Teenagers are welcome.

Location: George R. Brown Convention Center
Contact: 713-752-2582 and online.

Volunteer Houston

On Dec. 25, the organization's holiday initiative arranges visitations to nursing homes in three areas of town. Attend a meeting at 9:30 a.m. or noon at either location, divide into teams, grab copies of Christmas carols and holiday cards and head to visit with elderly residents, typically for one to one-and-a-half hours. Register here.

Locations: Various, including Central, Northwest and Katy.
Contact: Walter Black, 713-964-0229, walter3829@gmail.com.