Krishna Janmashtami celebrates the birth of Krishna some five thousand years ago. The eighth day following Raksha Bandhan is observed as Krishna’s birthday. According to some Hindu traditions, Krishna is not considered an incarnation of Vishnu because he is Vishnu.
Vishnu is supposed to have ten incarnations, the Dashavatars, nine of which have already taken place. They are
- Matsya – fish
- Kurma – tortoise
- Varaha – boar
- Narasimha – half lion half man
- Vamana – dwarf
- Parashurama – warrior
- Rama – supreme being
- Balarama – prosperous being
- Buddha – enlightened being, the most recent avatar of Vishnu/Krishna
- Kalki – the future and final of the ten avatars
The wiki article on the concept of avatar is quite informative and worth a read. As a Hindu, I ought to know this stuff well. It’s fascinating.
Anyway, Janmashtami greetings. Have fun.