I remember an english-speaking, most likely American, movie from the 90s or maybe late 80s about this boy and girl that constantly prank each other all the way into their adulthood. The pranks get bigger and bigger. I think one got pranked at his/her wedding. There might also have been some small tin can or item or token that they kept exchanging.
You are maybe searching for Love Me If You Dare a French movie starring Guillaume Canet and Marion Cotillard.
Plot from IMDB :
As adults, best friends Julien and Sophie continue the odd game they started as children -- a fearless competition to outdo one another with daring and outrageous stunts. While they often act out to relieve one another's pain, their game might be a way to avoid the fact that they are truly meant for one another.
So the movie is from 2003 and French, but the plot is quite what you describe and they exchange a tin box with a carousel painted on it.