Cloud Activities
Estimate how fast clouds move. Estimate their height by reference to cloud guides. Then measure the rate at which the angle of a cloud changes with time, using a triangulation instrument like a theodolite (used by surveyors) or a sextant (used by sailors). A simple protractor can also be used to make a rough estimate.

Do this for clouds at different heights (e.g.low cumulus and high cirrus) at the same time.

How Good is Your Maths?
If you are really ambitious, you can find the height of the low clouds by triangulating from two points at least several hundred metres apart.