Misc: Who sings the theme song to the television series Friends?

Questions

What is commemorated by the Hindu festival of Janmashtami?

Which chess computer made history by beating a grand master by a score of 3.5 to 2.5 in a series of games in 1997?

What was the name of the town in which Gilbert and Sullivans The Mikado set?

In the song which begins A frog he would a wooing go, who says Heigh Ho?

Which comedians catchphrase was Hello Playmates?