Open Stack

On 2015-07-07 15:15:35 +0800 (+0800), Tom Fifield wrote:
[...]
> There's one other subtly to throw in which is the fact that the paid
> ticket price need not be static - instead "name your price".
[...]

This is sort of what DebConf does, except they provide some
suggested registration fees for non-gratis participants:

    http://debconf15.debconf.org/registration.xhtml#registration

But basically if you want to go and you or your employer can't/won't
cough up enough € for professional or corporate registration, then
you attend as a private participant for free.
-- 
Jeremy Stanley