<p>It is mentioned on the <a href="http://en.wikipedia.org/wiki/Systems_Development_Life_Cycle" rel="noreferrer">Systems Development Life Cycle page on Wikipedia</a>:</p>

<blockquote>
  <p>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.</p>
</blockquote>

<p>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.</p>

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...