University of Tennessee engineering students got some sweet 'revenge' on their professors to celebrate Pi Day. 

Of course, it wouldn't be Pi Day without employing circular things that can be measured using the mathematical constant, so students loaded whipped-cream pies on circular paper plates.

The students then tossed said pies at their engineering professors. 

The messy event raised money for a good cause. Students paid $2 per pie and proceeds went to the Fort Sanders Ronald McDonald House. 

 "We thought this would be a good idea to give back the community and celebrate pi day as well," UT student Mariah Lafond said.

The group also sold actual pies for eating after the pie throwing.