Mundane generally refers to all non-SCA related things.
eg. Mundane clothes are your normal, everyday clothes. Other 'mundane' things are paperwork and responsibilities that relate to legalities in the SCA, signing waivers, dealing with city councils, all the 'behind the scenes' organisation that goes into running an event.
There are also terms or phrases that have different meaning in 'mundane terms' than in the SCA.
See also: modern
The other, and more mundane use of the word mundane (har har) implies that, as much of a surprise as it may be....
It's not all fun and games!
In fact, there are lots of jobs, as far as this editor can tell, that need to be done which are not very enjoyable.