Local library will have a list of places looking for volunteers, but I found a lot of them wanted you to do, say, every tuesday, or commit to 5 hours a week, where as I work 7 days in a row, then get 4-7 days off. I ended up picking up odd shifts in an oxfam ooh shop that was fun, working in a completely different environment to my normal job made it fun and I learnt some new skills (as well as getting seom cheap books!)