Hundreds of Palo Alto High School students dressed up in costumes and cheered on their classmates as Spirit Week 2013 kicked off Monday with Theme Day and a lunchtime rally at Viking Stadium, which ended with a senior victory in the year’s first major Spirit Week game.

As per tradition, seniors arrived at Paly in costumes reflecting their birth decade, the 1990s, rather than their class theme, “Survival of the Fittest.” The freshman class dressed based on their theme, “Caution,” the sophomore class came as their “Superhero” theme and the junior class as hippies, in reference to their theme “Yellow Submarine.” The themes, which originate from class colors (green for seniors, yellow for juniors, red for sophomores and orange for freshmen) will reappear on Friday when they form the basis for each class’s float and dance.

During the main event of the day, the lunchtime rally, the classes gathered in the football stadium’s stands and introduced their first cheers and chants. After several minutes of trading cheers, the first of the daily best dressed contests were held, followed by the day’s main event, Musical Chairs.

The seniors managed to come out on top in Musical Chairs — barely. After her partner, senior Andrew Frick, was eliminated in the first round, senior Callie Walker managed to stay in the game, finally besting junior Tess van Hulsen in the final round to win. The Class of 2015 also took third place, thanks to the efforts of junior Preston Kuppe, while sophomore Eli Friedlander came in fourth.

For an overview of scoring for Theme Day, click here. Winners of Best Dressed and Best Cheers will be announced, along with the current score of each class, after float building is finished tonight. Float building takes place after school, from 4 p.m. to 9 p.m, in the Autoshop.

According to Student Activities Director Matt Hall, points will be taken off from some of the classes for lack of sportsmanship and cleanliness at the rally. Hall did not specify which classes would be penalized. In addition, Hall said the rules to musical chairs may be revised for Spirit Week next year.

Spirit Week continues Tuesday with Salad Dressing Day.