In my school they have a carnaval celebration that turns the school a bit upside down. It is a long standing tradition. The 10th, 11th, and 12th grade nominate and vote for a representative to be on student council but is much like the carnival queen contest that used to be the tradition. What is really spectacular about it is that each class uses a theme, they plan a day of games for the 7th through 9th graders to court their votes for the winner.
This one had giant bowling pins you slide into.
Some videos from end of the games:
That night was the show for each of the three grades. They coordinated costumes and dances to fit the theme. At the end of each of the class choreography, the representative candidate was introduced and brought to the stage in a carriage float. Then there is a speech from the escort and then the candidate.
I took some videos of portions of the dances. Students have been working on this for several months and it was very exciting to see them work collaboratively for such a presentation.
The next day was voting. And the 11th grade one. Their candidate is now on student council and the grade had the bragging rights for the best coordinated plan and fun.