As TMN , Smeggers and Cybernight have said , try helping out at the back .
Practice getting tyres on and off by hand and replacing tubes , get it down to a fine art . Its amazing what a difference it makes on a ride if you have someone who can get punctures fixed quickly with no messing about , especially in the colder months/dark .
Struggling/Newer riders appreciate someone coming back to make sure they are ok , know where they are going , giving advise etc . You can even tell the ride leader what you are doing , this takes some pressure off him knowing there is an experienced rider at the back of the group keeping an eye out . There is a lot of satisfaction to be gained in gently bringing a rider back to a group .
If you normally ride with a faster group ( I`m guessing you may as you are racing ) once a month try riding with the slower groups . Dont go on the front and smash it though . Stay at the back and help out there , doing this will give your club something back .