There are probably more stars than black holes and so far we haven't been bothered by any of them . . . except for the one. ;o) http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q7.html
Nearest known Black hole is about 3,000 light years away but finding them can be tricky there might be a closer one on a collision course but the odds are somewhat against it!
high energy collisions in the upper atmosphere are causing micro black holes all the time, they evaporate in nano seconds due to HR. The LHC is really just an attempt to create those collisions in an observable situation.