One of my best technicians for the last 5+ years has decided to Leave and move back closer to her family. She has been a top notch employee and I really hate to see her go. Now like most work places we tend to joke around and have some fun and the guys play pranks on each other while mostly she would just watch and laugh. Well back about 5 months ago she tplayed a prank on it was even on me. Nothing over the top just had me searching for something she had hidden on purpose. I swore to her then I would pay her back and have yet to hold up my end. I would like to come up with a good prank but we have all done so many she is aware of them. Any good "clean" ideas?