It is mentioned on the Systems Development Life Cycle page on Wikipedia:
To manage this, a number of system development life cycle (SDLC) models have been created: waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, and synchronize and stabilize.
I found a few things on Google, but I felt that they were vague and they just didn't click for me. Perhaps an explanation from someone here might be more clear.
Waterfall is a model that enforces control and avoids parallelism; every requirement for a task has to be fulfilled before starting the task. Fountain says that a new task can be started before all requirements are met, because not all requirements are necessary at the start of the task.
Think of this: Super Mario Game,
Waterfall: first, design everything, then get hardware done (Hardware Team), then create some test sprites, then code the engine, then create artwork, then music and finish.
Fountain: while the hardware team is doing its job, artwork starts conceptual work, and coding starts some prototyping on preexisting hw. When artists and hw finishes, coders integrate these onto their code and continue 'til finishing the game...
As I understand it, they essentially contain the same steps but a fountain approach is much more iterative, with less focus on initial design and more on analysis.
You basically bodge your way through things. See what needs to happen, and improve it. See what needs to happen. Improve it.
It's more agile but at the cost of project stability. Waterfall is a lot better for large projects.
Fountain: Stand in a circle and throw some patterns and key words in the air to see where they land. Pick up only the ones that land inside the circle. Repeat until cancelled.
Waterfall: Wrangle everyone into a boat, then yell "Geronimo!" while going over Niagra Falls. Pick up the shattered pieces then rinse and repeat. Make sure it's well documented what part of the boat each individual should be sitting in, what they should be holding on to, how loud to yell, and exactly where they should land. See form 3684-B for additional instructions.
Spiral: Pick one team member and have everyone else spin them around in circles until dizy.
Build and Fix: Just throw it against the wall to see what sticks. If something falls off add some duct tape. Used gum may also work. Any part that won't stay stuck, just throw away.
Rapid Prototyping: Do exactly what the client asked for. Repeat until they figure out what they want.
Incremental: Only build the parts you want to, and only when you want to do it. An alternate version is to only build the parts they scream loudest for, and only when they are actually standing at your desk waiting for it.
Synchronize and Stabilize: Like Spiral except only one person at a time spins the unlucky team member. When their turn is over, stop the spinning for a moment.