At one stage we seemed to be changing campaigns every few weeks, due to the short attention spans of some of the players (me included). However, more recently I've been involved in two campaigns, neither of which show any sign of ending soon.
But an old 2ndEd game finished over a long weekend of Dragon Mountain. We fought kobolds by the hundreds! We smashed! We cast spells! We fought hand-to-hand! We pulled every trick we could think of!
Then we met the Dragon at the end of it. Despite the Dwarf invoking the power of Moradin and weilding the Axe of the Dwarven Lords, despite my Paladin having the old Wyrmslayer kit (remember that?), despite everything...the whole group died. Bah.
The DM is still promising that one day he'll convert Dragon Mountain to 3.5 and run it again, advanced a few years on. Hmmm...there's an idea.