Moomba is one of the largest free community festivals in Australia.   In Melbourne, it’s held annually over the labour day long weekend in March along the Yarra river.  A co-worker told me the name has aboriginal origins meaning ‘enjoy life’.  According to Wikepedia (very reliable I know, but I think they might be right on this one):

The official translation is “let’s get together and have fun.”

In 1981 Barry Blake in his Australian Aboriginal Languages spelled out the etymology in more detail:

Undoubtedly the most unfortunate choice of a proper name from Aboriginal sources was made in Melbourne when the city fathers chose to name the city’s annual festival ‘Moomba’. The name is supposed to mean ‘Let’s get together and have fun’, though one wonders how anyone could be naive enough to believe that all this can be expressed in two syllables. In fact ‘moom’ (mum) means ‘buttocks’ or ‘anus’ in various Victorian languages and ‘ba’ is a suffix that can mean ‘at’, ‘in’ or ‘on’. Presumably someone has tried to render ‘up your bum’ in the vernacular.

Furthermore, in 1969, Luise Hercus provided the following definition for ‘mum’ (i.e., ‘moom’) in The Languages of Victoria:

Mum: bottom, rump. The jocular Healesville expression

The whole thing is basically an enjoyable, family-fun summer festival.  

There are games and prizes ,

rides  ,

bike ramps (?) ,

music ,

all sorts of good food ,

and a parade to round it all off

The only downside to this long weekend of festivities was the aforementioned ‘end of the world’ storm we got in the middle of it.  Not the best time to have unsteady tents and temporary attractions set up along the river…