A phrase used, frequently after an argument between two other parties in the conversation or after something awkward has been said, to signal that the speaker is unsatisfied or uncomfortable with the subject matter of the conversation and wishes to change the subject.
Parody of how bout them cowboys?!
A: So I hear you're a Neo-Nazi and support the holocaust.
B: So...how 'bout them Cowboys?
A: You're a platypus-lover!
B: Well, you're a bitch!
C: So...how 'bout them Cowboys?