I pulled the Sunday Night Baseball schedule from another thread im participating in, did a quick back check, and figured id share the results.
April 4 - NY Yankees at Boston (ESPN2) Boston W 9-7
April 11 - St. Louis Cardinals at Milwaukee Brewers Milwaukee W 8-7
April 18 - NY Mets at St. Louis Cardinals St. Louis W 5-3
April 25 - Atlanta Braves at NY Mets NY Mets W 1-0 (6 inn)
May 2 - NY Mets at Philadelphia Phillies Philadelphia W 11-5
May 9 - NY Yankees at Boston Red Sox Boston W 9-5
May 16 - Philadelphia Phillies at Milwaukee Brewers Milwaukee L 4-2
May 23: N.Y. Yankees at N.Y. Mets NY Mets W 6-4
May 30: Texas at Minnesota Minnesota W 6-3
June 6: Milwaukee at St Louis St. Louis L 4-3 (10 inn)
June 13: Chicago White Sox at Chicago Cubs ChiCubs W 1-0
Not really a system (or anything too too significant for that matter) but certainly worth noting that the home team has won 9 of 11 games on ESPN Sunday Night Baseball so far this season, and roughly half of the games appear to have hit the overs.