Inventa really lends itself to the sort of mechanisms and structures that need to be developed for these field events.

Shotput

Create a (lever) mechanism that will project a small missile (rolled up paper) as far as possible within a set area. You will need to create the shotput range which fans out from the lever and is marked off appropriately. Anything landing outside this area is not allowed.

Discus

Create a spinning mechanism that will release its projectile at the appropriate point to fling it into the marked area (see above).

High Jump

Version 1 - Design and make a mechanisms that will "jump" over a bar that gets progressively higher.

Version 2 - Design and make a mechanism that will throw a (model) person over a bar that gets progressively higher.

Long Jump

Same idea as above but this time they must get as far lengthways as they can.