For Teresa Watson, it was the official start of Christmas.

Along with nearly 500 others, she and her family crammed into five rooms at the Western Pennsylvania School for Blind Children yesterday to watch the school's annual holiday program -- complete with multiple musical numbers, elaborate sets, lighting, choreography and costumes.

In addition to being legally blind, all of the children at the school have serious physical or mental disabilities.

So Ms. Watson watched her 18-year-old son, Tommy, who has cerebral palsy and uses a wheelchair, bob his head and wave his finger in rhythm with the loud music.

"He doesn't have a lot of movement, but he seemed to like the noise, the clapping," said Ms. Watson, of South Fayette. "You could tell he was happy."

And if the children were enjoying themselves, their parents were positively jubilant -- taking pictures and videos, hugging their children after performances and delivering Christmas cards to the teachers.

The school has held a major holiday program since 1994, said Roger Thomas, the school's music teacher and director of the event. Along with Ruth Marshall, a physical therapy assistant at the school and the holiday program's choreographer, he's been working on this year's program since October.

There's no one room big enough to hold such a large crowd, so the program takes place in five different rooms, which means five different themes, five set designs, five dance routines and five sets of songs.

The room where Tommy performed, an upstairs gymnasium, was decorated in a 1950s drive-in theme, with colored lights, replicas of convertibles and teachers and aides decked out in poodle skirts and bobby socks.

Shailen Abram, a 10-year-old at the school, played the keyboard and sang a raucous version of "Born to Hand Jive." The other children participated as best they could: A few sang and danced, others smiled and nodded, and most were spun around in circles in their wheelchairs by staff members.

The performance showcased the musical talents of Shailen, described as "our little Stevie Wonder" by Jillian Pritts, the school's coordinator for institutional advancement.

When the real Stevie Wonder played a concert in Pittsburgh last month, Shailen was invited to meet him after the show and the two ended up jamming on the keyboard together for 20 minutes.

But it also gave parents of the other children -- many of whom were in wheelchairs and nonverbal -- a chance to see their children at center stage.

"It's wonderful," said the school's executive director, Todd Reeves. "I've been in special education for 20 years and it's very rare when you can be in an event where children with significant disabilities are the stars of the show."

Many parents watched the performances with mixed emotions. "It's happy and sad," said Ms. Watson, who brings tissues with her every year. "It's sad because your child's not doing what every other child is doing on Christmas, playing with toys. But these children are so innocent -- they're holy. It's a beautiful thing."

And it's not just parents who show up every year at the holiday program. Yesterday's audience included board members, community members, the families of staff members and even parents of former students.

"Once you come to this and it becomes part of your holiday tradition, it's something that's hard to give up," said Ms. Pritts.

Ralph Ross, for example, has come to every one of the holiday programs. His 19-year-old daughter, Bailey, has been a student at the school since age 3. Her mom, two grandmothers, cousin and great-aunt came to see her yesterday as well.

Bailey -- who was born with Joubert syndrome, a malformation of the brain -- performed in a room decorated like a living room, with a fireplace, Christmas tree, piano and poinsettias.

Even though she couldn't participate in the singing, Mr. Ross could see that she was smiling, moving around and gazing at the lights on the room's Christmas tree (she has limited vision).

"When you see little boys and girls with a lot of different maladies, it breaks your heart but it makes you feel good," said Mr. Ross, of Franklin Park. "Nothing against the mall, but this is what Christmas is really about. It hits you in the heart rather than the wallet."