Lord Krishna mentions in the Gita that `among the months I am the maargashiirshha, maasaanaaM maargashiirsho.aham.h.‘ maargashiirshha shuddha ekaadashii is noted as Gitajayanti and is celebrated in December. Perhaps, the Gita conversation, in whatever form, took place during this time of the year. At least, it is an occasion to remember, religous or otherwise, the Gita as a sanskrit text.
GurupaurNimaa or VyaasapaurNimaa is also an occasion to remember Vyasa for the epic Mahabhaarataa (and many other texts) written for `the benefit of mankind.’
