My friend Sherry, in an online book group I'm in, pointed out this link. Possibly an idea if you have books you don't want, good balance, and not too much self-consciousness.
In other book groupy news, there is a new Persephone Reading Group recently started up in Oxford. It's meeting every six weeks, I think, and the next one (which will be my first) is June 4th, reading Flush by Virginia Woolf. I'm excited to meet other Oxford-based Persephone lovers - and if anybody reading this lives in or near Oxford and would be interested in meeting to drink wine and talk Persephone, for just £5 a meeting, then let me know! I don't know if the organiser, Claudia FitzHerbert, would want me broadcasting her email address - so if you're interested, email me on email@example.com and I'll put you in touch.