I don't want to be the awkward guy who turns up first session without having signed up...
A lot of clubs advertise their events, so that people can go to them and sign up afterwards if they actually like the club (have been invited by The Shakespeare Company, Monash Uni Role-Players and Board Game Society). So, you wouldn't be the "awkward guy".
But yes - there is clubs day. Meet them there, and they can sign you up. There's also the e-mail option, but they'll probably ask you to go to an event and sign up there.
Yeah one of them is recorded apparently but my mum went into a fit talking about wasting uni fees and bad arrangements blah blah blah.
There's not much that can be done, really - the uni offers so many units, you can't expect none of them to clash. Even really similar ones - hell, I've had lectures of CO-REQUISITES clashing before.