Normally, I would have done lots of googling before moving to a new country but with Peru, I’m playing catchup. Here are some expat sites from a quick trawl on Google:
I also hear that there is one called “liveinperu” but I can’t find it.
The blog of an expat.
For concerts: http://conciertosperu.com.pe/agenda-conciertos/ (including free ones or “gratis” in Spanish)
And because food is one of the major delights of living in Peru (picarones shown below): Peru Delights