There are several on their variety shows, especially T-ara Dream Girls.
There was a part in the first episode where Qri, Boram, Soyeon and Jiyeon convinced Eunjung and Hyomin that their designated jobs would be as scuba divers, and that they had to practice by sticking their heads in cold water and staying under for as long as they could. Both of the girls fell for it.
Watching Boram do a half-assed cartwheel for absolutely NO reason at all during her flight attendant interview while all of the other girls stood on one leg and held their hands out was hilarious.
Their English. Good Lord! It's hilarious to watch them prank each other, something they do quite often on their reality shows. They were put on the spot to introducethemselvesin English during their reality show T-ara Dream Girls.