So it was a public event attended by 450 people:

Even names match up, but oddly the date is different.

elmomle 2 hours ago | parent | next [-]

Your links are for the inaugural (first) ball in December 2011; OP's text referred to a second annual ball in December 2012.

	▲	pests 17 minutes ago \| parent [-]
		You are right my first is incorrect but the second does seem to be from 2012.

nialv7 an hour ago | parent | prev [-]

looks like we have it. in the end it's pretty mundane...