I know I'm repeating myself here - and that hardly anyone will pay attention to this - but...
Dead Men Racing. Public server with admins online daily, busiest between 7pm and ~10pm GMT. Racing is as clean as you're likely to find, all mature and fair and very friendly people. Combo's change weekly with a 1hr race on Thursday nights. Even though I don't race LFS myself anymore I still think dMr is one of the best places to race if you're looking for fair and fun pickup racing and don't care about some ranking or licensing system. dMr is proof that it
is possible to run a fairly popular public server successfully and keep crashers and the like out for many years. Of course, you won't see the numbers of drivers there that you see on IHR, for example, but the racing is infinitely cleaner and more fun.