* Astronomy

On February 28 2013, a third Van Allen radiation belt was reported to be discovered. 
http://en.wikipedia.org/wiki/Van_Allen_radiation_belt

The 1925 Charlevoix-Kamouraska earthquake struck northeastern North America on February 28, 1925
http://en.wikipedia.org/wiki/1925_Charlevoix%E2%80%93Kamouraska_earthquake

The 1997 Ardabil earthquake was a destructive earthquake that occurred on 28 February 1997.
http://en.wikipedia.org/wiki/1997_Ardabil_earthquake

"March 0" is sometimes used by astronomers as a synonym for the last day of February
http://en.wikipedia.org/wiki/March_0

The largest find of Iguanodon remains to date occurred on 28 February 1878 in a coal mine at Bernissart 
http://en.wikipedia.org/wiki/Iguanodon#Bernissart

The sarcophagus of King Psusennes I was opened on the 28th February 1940 
https://en.wikipedia.org/wiki/Psusennes_I

Steven Chu (born February 28, 1948) is an American physicist
http://en.wikipedia.org/wiki/Steven_Chu

Daniel Chee Tsui (born February 28, 1939) is a Chinese-born American physicist 
http://en.wikipedia.org/wiki/Daniel_C._Tsui

Cornelius (or Cornelio) Gemma (28 February 1535 - 12 October 1578) was a physician, astronomer and astrologer
http://en.wikipedia.org/wiki/Cornelius_Gemma

François Jean Dominique Arago (1786-1853), was a French mathematician, physicist, astronomer
http://en.wikipedia.org/wiki/Fran%C3%A7ois_Arago

Sidney Wilcox McCuskey (February 28, 1907 - April 22, 1979) was an American mathematician and astronomer.
http://en.wikipedia.org/wiki/Sidney_Wilcox_McCuskey

Jost Bürgi (28 February 1552 - 31 January 1632) was a Swiss clockmaker and maker of astronomical instruments
https://en.wikipedia.org/wiki/Jost_B%C3%BCrgi

Star Trek: "The Cloud Minders" was FIRST broadcast on February 28, 1969.

Spoiler

The Five-year WMAP data were released on February 28, 2008
http://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy_Probe#Five-year_data_release

GRB 970228 was the first gamma-ray burst (GRB) for which an afterglow was observed. It was detected on 28 February 1997
http://astronomy.activeboard.com/t41410971/grb-970228/

Supernova 2002bj in NGC 1821 was discovered on Feb. 28
http://astronomy.activeboard.com/t32072190/supernova-2002bj/

Percy Molesworth discovered a "great disturbance" in the southern bands of Jupiter on 28 February 1901
http://en.wikipedia.org/wiki/Percy_B._Molesworth

Asteroid (184) Dejopeja was discovered by J. Palisa on February 28, 1878.
http://en.wikipedia.org/wiki/184_Dejopeja

Asteroid (193) Ambrosia was discovered by the French (Corsican) astronomer J. Coggia on February 28, 1879
http://en.wikipedia.org/wiki/193_Ambrosia

Three bright objects sighting, by witnesses aboard the U.S.S. Supply, on February 28, 1904 
http://astronomy.activeboard.com/t56864763/meteor-of-28-february-1904/

2008 TC3 meteorite fragments were found on February 28, 2009
http://en.wikipedia.org/wiki/File:323213main_Petersmeteorites_946-710.jpg