Home Run Antics:
After hitting a home run, press L1 or R1 while your player is rounding third to make him gesture towards the crowd. The crowd will boo if you're away, and cheer if you're the home team. 

Odd Commentary:
Leave the game alone long enough and the announcers will start up some crazy commentary?. Crazy! Also, sit on the mound long without throwing a pitch for a while and the announcers will go crazy again? Super Crazy! 

Make Them Good:
While playing a franchise, go to the main menu of franchise mode and select "GM Office" then "Roster Management". Now select "Player Editor" and then select your franchise team. After finding your team, the game will show a list of all the players on it. Go down to any one of them and you will be able edit their attributes to make them the best as possible. Do this to every one of your team members to dominate the league. It's cheap, but who cares. 

Easy Card Points:
Select quick play or franchise mode. Set the number of innings to 1 then score by any means while holding the CPU to a no hitter. When the single inning game ends, you will be awarded card points for having a perfect game and a no hitter.