Boost your confidence, meet new people, bolster your cv and meet a range of new and interesting people. There are literally thousands of organisations and charities in need of your expertise and enthusiasm, if you have some spare time, then donate it! There are many online resources such s do-it-org.uk and timebank.org.uk where thousands of opportunities are available.
Roles vary as widely as donating a couple of hours a week to mentor a teenager to working as a teacher in Ghana teaching IT skills for several months. So if you are struggling for work or you would like to give something back then you can always consider volunteer jobs.