There's a line, and it's really not even a fine one, between roasting and toasting. We've all probably been at a wedding where the best man has had a little too much to drink and falls into the TMI zone. It's so common it's become a movie cliché in itself. If you want to tell some amusing stories, then you should do so, but rarely at the expense of the groom, and absolutely never at the expense of the bride. Be sensitive to the fact that this is a very special day for almost everyone there, and it's always better to keep it light.