It's August 2015, and to follow on with the success of last year's #RPGaDay event, David Chapman at Autocratik has created a new list. Each day in August, I'll be posting my "answer" to that day's topic.
The longest campaign I ever played in was probably the D&D 3rd Edition game that took place over about two years. I've had other games technically go that long, but with more breaks than the D&D game, which was played pretty reliably in comparison. With my well-documented "Ooh Shiny Syndrome," it would be the one and only 3rd Edition campaign I'd complete.