The most runs scored in a single game by a single player since 1950 was 7 done by Boston's Spike Owen in 1986.
The most runs scored in an inning by both teams is 19 in the 8th inning of a game between Cleveland and Boston in 1977. Cleveland scored 13 runs and Boston scored 6. The most runs scored by a single team in aninning is 18 by Chicago against Detroit in the 7th inning of a game played in 1883.
The most runs ever scored against the St. Louis Cardinals during a single game was 28. This was accomplished on July 6, 1929 by the Phillies.
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
The Yankees scored 25 runs in a game against the Philadelphia Athletics on May 24, 1936.
Once the Red Sox scored 17 points in one inning.
13. The Tigers scored 13 runs in the 6th inning of a game against the Yankees in 1925 and the 9th inning of a game against the Texas Rangers in 2001.
30, by the Rangers against the Orioles in 2007.
Brian Lara has scored 400* in an inning.