Yup, quite a few of them are happening around the world - the overall 'movement' is / can be called the 'cryptoparty movement' (if one could say it was indeed a 'movement'). We did our own event in our local town (http://cryptoparty.lt/) (well, "i participated in one" is more like it), and hopefully we'll pick it up and do it again.
There's always this delicate thing of having a balance between being interesting to local hackers, vs. being understandable by laypeople. We veered towards the former, and it was great fun, but it would be very beneficial to try and be more welcoming towards the general crowd, too. It's not always easy when introducing complex technologies - I try to avoid using leaky metaphors, but sometimes that's not possible.
There's always this delicate thing of having a balance between being interesting to local hackers, vs. being understandable by laypeople. We veered towards the former, and it was great fun, but it would be very beneficial to try and be more welcoming towards the general crowd, too. It's not always easy when introducing complex technologies - I try to avoid using leaky metaphors, but sometimes that's not possible.