The required location is dependent on the nature of the events.
At the elementary level, it would be simple to hold the events in
the classroom. The material required would be minimal and you could
make use of everyday household items.
At the secondary level, it might be difficult to incorporate the
Olympics directly in the classroom environment. It might be simpler
and more successful to organize the Olympics as an extra-curricular
event. A science club or a group of interested students and/or teachers
could put together an Olympics. The school building itself could
provide the places in which to hold the events. For example, you
could make use of the school gym, cafeteria, hall-ways, classroom,
parking lot and football fields.
Other locations outside the school ground could include community
and/or shopping centres, universities, parks and even home or church
basements. There should be plenty of space and the public should
know the location of the event.