Union Memorial Hospital's hospice program will hold an open house from 2 to 5:30 p.m. tomorrow in the hospice office at 114 E. 33rd St. to celebrate its 10th anniversary and to attract potential volunteers who are greatly needed. The public is welcome. Details: Call Amy Strong or Debbie Mason at 554-2800.
The 100th annual Columbus Parade will be held on Oct. 7, one day prior to Columbus Day. Volunteer parade marshals are needed to check units, assist in parade formation and line-up, maintain proper spacing between units, with traffic direction and with parade dispersal. The parade begins at 2 p.m. on Key Highway at Covington Street and ends about 4 p.m. on Central Avenue near Fells Point. Call Shelia Goodwin by Sept. 21 at the Baltimore Office of Promotion, 752-8632.
''Developing a Drug Free Workplace'' is the topic of a breakfast meeting at 7:30 a.m. Sept. 26 sponsored by the Chesapeake Occupational Health Program at Colonel's Choice Restaurant on 40 in Aberdeen. Tickets are $7 and must be purchased in advance. Tickets and details: 893-0322.
Baltimore Zoo will hold orientation classes for volunteers at 7:30 p.m. Sept. 27 at the zoo. For details about volunteering, call 396-7623.
Multiple Sclerosis Society needs volunteers to help immediately and through Oct. 31 for its fund-raiser, a competition among bars and restaurants called the U.G.L.Y. Bartender contest. Volunteers will contact potential participants, follow up with registered bars and process materials for the event. Call Dee Myers, 821-8628.
Governor's Office on Volunteerism is offering a workshop for volunteer administrators, which will be held in October in two locations. From 11 a.m. to 1 p.m. Oct. 15 at the Catonsville Community College, Building Q, and from 11 a.m. to 1 p.m. Oct. 16 at Harford Community College in Joppa Hall. Registration of $5 includes beverage (bring your own lunch). For registration and other information, call 225-4496.
The Home Team of Pikesville Senior Center, 1301 Reisterstown Road, wants volunteers to help homebound senior citizens ages 60 and over who are residents of Baltimore County. One hour a week is asked. Call Gail Rubenstein, 887-1245.
Maryland Science Center needs volunteers for bus greeters, science demonstrators, to help with center events, as salesclerks and with mailings. Call 685-2370, Ext. 355.
St. Vincent de Paul Society will celebrate its 125 years of caring for neighbors in need with a banquet and dance on Sept. 21 at the Sheraton Inner Harbor Hotel. For details, call John J. Schiavone, 547-5377.
Jewish Big Brother/Big Sister League of Baltimore has produced a videotape designed to explain the agency's mission and attract volunteers. Bob Turk, WJZ-TV weatherman, is host and narrator. For those who want to arrange a showing of the tape, call 542-6300.
Special Olympics Maryland wants volunteers who can be data entry operators, record keepers and coordinator of monthly acknowledgments. For details, call 931-4100.
The Baltimore County Department of Recreation and Park Office of Therapeutic Recreation Services wants volunteers to work with intellectually limited young adults as assistant directors for their musical theater program. Volunteers should have an interest in music or theater and have a desire to help others. Rehearsals begin this fall at various locations around the county. If interested, call 887-5370.
Hearing and Speech Agency wants good used toys such as rattles, musical balls, pianos, jack-in-the-boxes or any others for ages 6 to 24 months for its Parent-Infant-Toddler program. Call K.C. Docie, 243-3800, or bring toys to 2220 St. Paul St., Baltimore 21218.