Along with many other lawyers, I do pro bono work quite freqently for family, friends, and sometimes even strangers.  Although there have been exceptions that were complicated and lengthy, the usual tend to be relatively uncomplicated, straightforward matters that are disposed of within a fairly short time frame. 

I'm not saying it's never occurred, but I don't know of many lawyers who have taken on huge corporate cases that are expected to last years and be quite costly, yet have no real chance of a likewise huge payday.  The movie "A Civil Action" is a good example of what I'm talking about.