Where English speakers have a tradition for standing on a soapbox to make a speech at a more or less informal meeting, Danes use a beer crate.
(Speakers´ Corner in Hyde Park is the most famous venue, but not the only place people get up on a soap box...)
https://en.wikipedia.org/wiki/Soapbox

The English expression does not have quite the same implication that there was beer in the crate, which was handed out to the audience. If one of these meetings is held at a workplace, there may well be soft drinks or coffee served.
Beer is not allowed at many workplaces, so it might or might not be permitted at a meeting after working hours.

Otherwise an ´ølkassemøde´ is a fairly informal information meeting.
Local politicians hold them when campaigning for election, and groups and societies hold a sort of ´round table´version, where a chairman or speaker makes a proposal and then accepts questions or discussion.
http://m.bt.dk/?article=14668972-Pia-Kjaersgaard-Jeg-vil-ogs...

The meetings here are more information meetings:
http://universitetsavisen.dk/politik/olkassedemokrati-pa-nat...