The Google doodle has a bunch of people splashing the letters in red, blue, green purple and yellow as they rush past in search of possibly their next prey. Just as they've explained it themselves, "Amid the cloud of red, blue, yellow, green, and everything in between, festival-goers can often be found laughing, singing, and dancing in the streets."
The celebration of Holi has various religious beliefs and mythological stories associated with it. It lasts for two days. The first day is known as Holika Dahan or Chhoti Holi and the second as Rangwali Holi, Dhuleti, Dhulandi or Dhulivandan.
The first day, or Chhoti Holi, was celebrated on Sunday, when people lit the traditional bonfire in the evening to symbolise Holika Dahan, a story which finds its roots in Hindu mythology. On the second day, the festival of Holi is celebrated, wherein people smear each other in colours, a tradition that is supposed to signify the colour-play between Lord Krishna and the gopis.
Holi is also celebrated as the triumph of a devotee. As the legend depicts that anybody, howsoever strong, cannot harm a true devotee. And, those who dare torture a true devotee of god shall be reduced to ashes.