If you are talking war...
I personally thought Washington's gallant parading in the face of the entire line of Clinton's regulars at Monmouth to induce action and inspire a crucial tactical victory was pretty courageous. Had he fallen, America would have as well.
Other favorites of mine:
Arnolds charge at 2nd Saratoga 1777
Pickett's charge at Gettysburg 1863
Waynes suicidal raid on Stony Point 1779
Ferguson's last stand on Kings Mountain 1780
Kosciuszko's impossible victory at Raclawicz 1794
Jasper's replanting of the flag at Ft Sullivan 1776
too many more to mention...