Quickie:

A multiple activity event based around pumpkins

Pro Tips:

Thoroughly plan out the logistics of your event - how many pumpkins will you need? How many teams will you have? How many students do you expect?
Get bandannas or face paint to distinguish teams, build camaraderie and to add to the fun of the night.
Buy a plastic pumpkin, spray paint it gold, present it to the winning team at the end. Consider having them sign it and doing this yearly.

Divide group into teams and designate a team captain (this can be a leader)
The captain can help students sign up for various events - make sure every student on a team is involved in at least one event. Otherwise their team is disqualified. This means teams have to strategically place their best players at certain events.
Create a list of events that your students could participate in - make sure they don’t all depend on athletic ability.
Figure out how many students from each team will be needed for each event.
Create a point system. If you have 6 teams - give the team that comes in first in each event 6 points and the team that comes in last should get 1 point. Add up the points at the end to see which team won the olympics.

Event Ideas