Vishwakarma Puja is usually celebrated in the workplace and always on the roof of the shuktara boys house in Kolkata. Essentially this is a Puja where workers have their tools blessed. This is what Wikipedia says about this festival:
It is generally celebrated on 17 or 18 September in Indian states such as Uttar Pradesh, Karnataka, Assam, West Bengal, Bihar, Jharkhand, Odisha, and Tripura. The festival is observed primarily in factories and industrial areas, often on the shop floor. As a mark of reverence the day of worship is marked not only by the engineering and architectural community but by artisans, craftsmen, mechanics, smiths, welders, industrial workers, factory workers and others. They pray for a better future, safe working conditions and, above all, success in their respective fields. Workers also pray for the smooth functioning of various machines. It is customary for craftsmen to worship their tools in his name, refraining from using the tools while doing so. Modern electronic servers are also worshipped for their smooth functioning.
Special statues and pictures of Vishwakarma are normally installed in every workplace and factory. All workers gather in one common place and perform the puja .
Below are more photos from shuktara's rooftop celebration...
Every year in August the 'sisters' of shuktara come to the boys home and tie rakhi on the wrists of their 'brothers' to show their affection. Across most of India the same thing happens - with brothers and sisters who are related by blood but also when that strong family bond is felt between unrelated people. It is a celebration that everyone at shuktara can participate in, and everyone enjoys this festival immensely.
[from Wikipedia] Raksha Bandhan in Sanskrit literally means "the tie or knot of protection". The word Raksha means protection, whilst Bandhan is the verb to tie. It is an ancient Hindu festival that ritually celebrates the love and duty between brothers and their sisters. The sister performs a Rakhi ceremony, then prays to express her love and her wish for the well being of her brother; in return, the brother ritually pledges to protect and take care of his sister under all circumstances.
The festival is also an occasion to celebrate brother-sister like family ties between cousins or distant family members, sometimes between biologically unrelated men and women. To many, the festival transcends biological family, brings together men and women across religions, diverse ethnic groups and ritually emphasizes harmony and love. It is observed in the Hindu calendar month of Śrāvaṇa, and typically falls in August every year.