that's a good one
That's quite funny or clever. Sometimes used ironically to indicate that what was said was foolish or unbelievable. That's a good one! Did you come up with that yourself? You think companies deserve a tax cut so they can pay more to their employees? Ha, that's a good one.
ˈthat’s a good one
(informal)
1 said in reply to a joke or clever remark
2 (ironic) said in reply to a stupid remark or action: ‘Can you make dinner? I’m tired.’ ‘Tired? That’s a good one. You’ve done nothing all day!’