Not sure if this is the type of stuff you're looking for, and it happened today, but I'll say it anyway...
I just got a phone call off the Sri Lankan guy I'm buying a car off. My mum answered my phone and thought it was my brother putting on an accent, so she decided to put an accent on too. She said I was in the shower (in a poor Sri Lankan accent) and he went silent, then told her who he was. She realised the mistake she had made but it was too late to change back, so she just pretended that's how she talks.
I guess my mum is a fu*kwit