A really lovely Autumnal tradition to start with kids and as cheap as chips (e.g.: free) Just head to the most colourful clutch of trees you can find and look for leaves of all hues. Once collected, arrange them artfully in a spectrum and photograph, craft with or just admire the beauty. If you really enjoy this, then a special trip to an arboretum or a lovely open garden will yield the greatest range of treasures, but even a meander through a leafy city centre should supply you with enough colour to brighten the day.
They make wonderful foliage crowns, woven together as you do a daisy chain. You can make mandalas and foliage patterns on the floor or table, stick them in a collage, turn them into colourful clothes on paper dolls or just place them prettily in a bowl of water and admire their tones...
To preserve leaves gather short branches of laurel, lime, hornbeam, eucalyptus, beech and maple and stand them in a bucket of warm water for a few hours. If any curl and wither, then discard them. Make a mix of glycerine (1 part) and water (2 parts), boil it up and, once cool, stand your short branches in it, ensuring it's at least 6 cm deep in the bottom of your container. After several weeks the branches and leaves will have soaked up enough glycerine to be preserved and you can use them in wreaths and foliage displays.