I was cleaning a house on a high street with my trolley the other week and the woman next door laughingly said, "Mine are filthy, fancy doing em for free". She disappeared inside and while she was away inside I did them for her. I packed the gear away and off I went feeling all warm inside lol.
Last year I used my Chrimbo tips to buy food for the local foodbank and to be fair i'm happy to do extras. Here in Wales there are lots of chapels (as opposed to churches). They are pretty big affairs usually, with 4 huge windows on each side. I've done 4 or 5 for free now, along with the odd village hall.
I'm not saying i've saved the world or anything, just to say that it gives a really nice feeling and you should give it a bash - it's great to be able to give something back into the community that provides you with what I have to say is a damned good living.