On Friday, 21 May 2010, on the 30th anniversary of the arcade game Pac-Man, Google unveiled worldwide their first interactive logo. Anyone who visited Google could play Pac-Man on the logo, which featured the letters of the word 'Google' on the Pac-Man maze. The logo also mimicked the sounds the original arcade game made. The "I'm Feeling Lucky" button was replaced with an "Insert Coin" button. Pressing this once enabled you to play the Pac-Man logo. Pressing it once more added a second player, Ms. Pac-Man, enabling 2 players to play at once, controlled using the W,A,S,D keys, instead of the arrows as used by Player 1. Pressing it for a third time performed an "I'm Feeling Lucky" search. It was then removed on Sunday, May 23, 2010, initially replacing Pac-Man with the normal logo. Later on that day, Google released a permanent Google Pac-Man site, due to the popular user demand for the playable logo.
Five blue dots, three red dots, three yellow dots, four blue, three green and two red: yes, it's Google spelled out in Braille. This was issued on 4 January 2006, in celebration of the 197th birthday of Louis Braille, who invented the embossed-point alphabet for blind and visually impaired people.
Google's August 29th logo celebrated Michael Jackson's birthday a couple of months after his death. The two Os in Google were replaced with two feet, en pointe, wearing patent leather shoes and shiny white socks below slightly-too-short trousers.
20th anniversary of the Wallace and Gromit Characters.
On March 2010, the Pi Day, 3.14 was celebrated by math nerds and Google, worldwide. Having been conspicuously missing from Google's ever-growing repertoire of special-event doodles for years, Google finally relented and unleashed its inner nerd, not that it tried to hide it too hard in the past. And, perhaps to make up for all the years it skipped, Google went all out this time and showed off six common uses of the famous number. The Pi Day Google logo starts off with the formula everyone knows (?) for the area of a circle A = πr2, but goes on with some more advanced stuff. The two 'os' in Google are used to represent the sin(x) function over a 2π period.
Google unveiled this logo to celebrate the 400th anniversary since Galileo Galilei, the Italian astronomer, showed Venetian merchants his new creation, a telescope.
This doodle that appeared online in Sept 2010 was meant to celebrate the 50th anniversary of the Flintstones.