Schools are converted into dark labyrinths, with monsters and ghosts instead of teachers. Musicians select their creepiest-sounding repertoire. And beautiful mansions are transformed into haunted houses.

With Halloween on its way, the Palo Alto area has a variety of activities for both children and adults. Here are some of the options for venturing out and exploring the happenings ... if you dare.

Santa Rita Elementary School holds its 49th annual Witches' Delight Carnival on Oct. 30 from 3 to 8 p.m. Amusement park rides include the "Frog Hopper" and the new "Wild Raft," with other attractions planned such as games, a cake walk, an obstacle course, cookie decorating and a costume contest. Admission is free, with activity tickets $1 each. Proceeds benefit the school's PTA. The school is at 700 Los Altos Ave. in Los Altos. Go to www.santaritaschool.org.

On Saturday, Oct. 31, Giancarlo Aquilanti conducts the Stanford Wind Ensemble and Martin Fraile conducts the Stanford Symphony Orchestra in a Halloween concert. Music on the bill includes selections from Mussorgsky's "Pictures at an Exhibition" and Wagner's "Ride of Valkyries." The performance will take place at 8 p.m. at Stanford's Dinkelspiel Auditorium. Tickets are $10 general, $9 for seniors and $5 for students. Go to music.stanford.edu or call 650-725-ARTS.

James Welch gives his 17th annual Halloween pipe-organ concert at St. Mark's Episcopal Church at 8 p.m. Saturday, Oct. 31. The program includes the Symphony No. 1 by Louis Vierne (the nearly blind organist at Paris' Notre Dame Cathedral in the early 1900s). Welch has to use what looks like super-human coordination to manipulate the enormous pipe organ, and that coordination will probably be most important in "Toccata in D minor for Chainsaw and Organ" (which incorporates power tools). The spine-tingling sound of the organ resonates particularly well in the church's high vaulted ceilings. Tickets are $10 for the concert, which is at 600 Colorado Ave. in Palo Alto. Go to www.welchorganist.com.

Lytton Gardens residents welcome tots through fifth graders on Saturday, Oct. 31, with free trick-or-treat bags, spooky stories, face painting and refreshments. The free event held at the senior community happens from 6 to 7:30 p.m. at 656 Lytton Ave. in Palo Alto. Go to www.lyttongardens.org or call 650-328-3300.

Many businesses along California Avenue in Palo Alto welcome kids under 10 years for trick-or-treating from noon to 4 p.m. on Halloween afternoon. Orange fliers in store windows show which businesses are participating.

Also on Oct. 31, the Bay Area Country Dance Society presents a costume ball. The potluck contra-dancing party features special "ghost callers" and the band Swing Farm, along with a costume contest. Held at the First United Methodist Church at 625 Hamilton Ave. in Palo Alto, the event is $18 general and $16 for members. The dance party starts at 8 p.m., with a free dance lesson starting at 7. Go to www.bacds.org.

After the 31st, several Palo Alto community Day of the Dead events are planned on Nov. 1. Festivities include art activities at the Palo Alto Art Center at 1313 Newell Road from noon to 4 p.m. (community altars, decorated sugar skulls); storytelling at the Children's Library at 1276 Harriet St. at 1:30 and 2:30 p.m.; and dance performances at the art center at 4. Go to www.cityofpaloalto.org/artcenter or call 650-329-2366.