Mark Grace

Broadcasting 101 -- ya may not wanna call your ex-wife a "dingbat" on live TV ... 'cause everyone knows that's pretty bad, right?? But, former Chicago Cubs star Mark Grace must've missed that lesson ... and now he's apologizing for his bizarre rant during Saturday's game. The 56-year-old joined…

Former Chicago Cubs superstar Mark Grace was arrested for drunk driving in Scottsdale, Arizona on Memorial Day ... and according to the police report, Mark has good taste in scotch. According to the police report, obtained by TMZ, cops observed Grace in his 2009 Jaguar weaving in and out of his…