We were in Bansko last week. It snowed mid week providing some great snow conditions. If the conditions are right and you fancy some mild off piste action, try going off to the right of run no 11 at the very top of the mountain, heading towards the fun park. Great fun dodging between the small bushes, particulary on a board. After this, if your brave enough, try the ramps and rails at the fun park. No sign of any half pipe, this year or last though, despite being marked on the piste map.
Great fun that area. If you are felling even more adventurous take a short (20min) hike to about mid height of the main peak above the bubble lift at the top and take a left down the couloir/chute. However, make sure that the snowpack is safe - awesome fun!!!