Google modifies their home page by including birthdays of some major personalities around the world or major events. Here are some of the best, unique and presented in more than one country. The list below is not any particular order.

2009.05.20 – Charles Darwin Birthday

2009.11.13 – Water on Moon found

2009.10.02 – Mahatma Gandhi

1998.10.29 – Google Beta

1998.08.30 – Burning Man (One of the first of Google’s modified logos!)

2006.01.04 – Louis Braille’s Birthday

2008.05.16 – Laser Invention

2009.10.07 – Barcode Invention

2003.03.14 – Einstein’s Birthday

2006.02.11 – Olympics Snowboarding

2007.04.22 – Earth Day

2005.04.15 – Leonardo Da Vinci Birthday

2008.11.04 – US Election Day

2009.05.20 – Darwinius Masillae

2009.01.28 – Jackson Pollock Birthday

2002.05.20 through 24 – Dilbert Comics

2005.03.30 – Van Gogh’s Birthday

2006.12.12 – Edvard Munch Birthday

2008.06.06 – Diego Velazquez’s Birthday

2007.04.01 – April Fool Day   — (TiSP)

2009.02.12 – Samuel Morse Birthday

2004.02.03 – Gaston Julia’s Birthday

Fractals 

2009.10.29 – Asterix Comic’s 50th Anniversary

2008.01.28 – 50th Annivesary of the LEGO Brick

2009.10.31 – Happy Halloween

2008.01.01 – 25 Years of TCP/IP protocol