Money would be a problem - let's say that nothing should cost more than £10. This means no hardback books, few concerts (though students get into CBSO events for £5 - the classical world is actually really generous to low-earners because it's a condition of getting massive public subsidies) and few gigs.
Books are easy - we can use charity shops, ABE (global second-hand book shop network) and Amazon's used books, and cheap CDs or illegal downloads are fine. We could also cover free things - TV, websites, Youtube, walks and places to go, all taking photos on a particular theme: anything really, as long as we can all do it within a month.
Everybody's invited, so tell your friends. and you're welcome to remain anonymous. But this comes with responsibility. You have to play the ball, not the man. This means that you can despise whatever that month's thing is, but you can't abuse the person who suggested it, or those who like it/don't like it.
We should do something different every month, as Cynical Ben suggested. So a book can't follow another book. However, you should have a go at everything, even if you don't like the sound of it. I'd like us all to be surprised by something.
Many of you are students: no suggesting things you have to write an essay about! Likewise, I won't suggest anything simply because I know a lot about it, or because it's 'educational'.
Everybody will get their turn to suggest something, and nothing legal will be excluded. I hate horror films and eating fish (actually cheap restaurants and recipes might be an idea), but if that's what comes up, I'll do it.
That's all I can think of right now, so add your thoughts (and we'll need a name).