I really like today's google doodle honoring the 189th birthday of Gregor Mendel. One of my best reports in grade school was about Gregor and his peas.
These are some of my favorites doodles from the past few months:
200th birthday of Robert Bunsen
50th Anniversary of the first man in space
Canadian Election Day
Columbian Independence Day
Les Paul's 96th Birthday
Richard Scarry's 92nd Birthday