20 by the Brewers over the Pirates at PNC Park Pgh. PA 4-22-2010
The most runs scored in a single game by a single player since 1950 was 7 done by Boston's Spike Owen in 1986.
By Australia
7
The most runs scored in a single inning by the Baltimore Orioles was 12 against the Tampa Bay Devil Rays on April 11, 2002.
13
Ricky Ponting has scored the most test runs for Australia - as of the end of the test series against Pakistain in England in July 2010 he had scored 12,026 test runs.
The most runs scored by the Padres in a single game was 20 against the Expos in May, 2001 and against the Marlins in July, 1996. http://sandiego.padres.mlb.com/sd/history/single_game_records.jsp
Of the top 8 single season leading runs scorers, only two of them ocurred after 1900. In 1921, Babe Ruth scored 177 runs (which is tied for 2nd all time behind Billy Hamilton's 192) and Lou Gehrig scored 167 runs in 1936. For seasons played after 1950, Jeff Bagwell has scored the most runs in a season with 152 in 2000.
Darren lehamann from austrailia
In 2010, the Philadelphia Phillies scored 772 runs during the regular season. They scored an additional 33 runs in the playoffs.
13 runs in the 4th inning April 13, 2003 at Cincinnati Reds.
Sir Donald George Bradman scored 309 runs in a single day's play on 11th of July 1930 and to this day remains the only player to score over 300 runs in a single day.