Jazzfest and Just for Laughs both attract many tourists as does Gay Pride(though this affects the hotels more east rather than west (Think Hotel Lord Berri vs Hotel de la Montagne)
Franco Folies doesn't pull in many tourists but since it is in-between the Jazz fest and the Just-for-Laughs, the hotels are often busy anyway...
While there is the Montreal International Film Festival which was on from Wednesday of last week until today. Pretty entertaining, but I couldn't find the "porn" category.