It's September, it's sunny, grab your boots and get outside with the kids to gather damsons from the hedgerows and go home and make jam with them. Damson jam is seriously good, homemade damson jam tastes nothing like the stuff you get in the jars in shops which is just about always way too sweet.
Homemade damson jam is worth all the time it takes to remove the stones from the middle of the fruit, this does take time, serious time, probably the best of an hour of two if you're doing it on your own so don't - get the kids to help. It is worth it too. Also you don't use jam sugar, just normal granulated or caster sugar as damsons are really high in pectin so it sets very easily.
Try it, it's really really good, also 1kg makes around 5 jars so you've got homemade Christmas pressies already waiting for Grannies and Aunts, damned efficient for September.