Members of the Maharashtra Navnirman Sena on Saturday celebrated the 40th birthday of their leader Raj Thackeray by organising blood donation camps and other social activities.However, the MNS refrained from holding a Hatt Puja programme, a take-off on the Chhat Puja performed by north Indians, which has become a bone of contention between MNS and migrants from Uttar Pradesh and Bihar.Over 20,000 supporters visited the MNS chief's home at Dadar and greeted their leader.