A financial products company wanted a visualization tool that would let a customer enter their wealth, pick a variety of investment strategies, spending strategies, and retirement durations, and then see how it all played out over historical data.
You could scrub a timeline back and forth to change the starting year, and see your weath and spending charted out over the course of that retirement.
It was best retirement savings education I've ever seen. Almost every retirement planner just shows you averages, and life looks simple and predictable. Reality is very, very different.
Things I learned:
1. The stock market will probably crash at some point during your retirement, and you will loose half of any wealth you have in it.
2. In spite of the big drops, the higher compounding rates of stocks mean that a bond heavy retirement gives you way less money, even in the worst market retirement years. 30 years lets money grow for a long time.
3. Attempting to spend as much money as possible drastically increases your odds of running out of money, or suddenly having a lot less to spend. (Seriously, what is up with people attempting to run out of money exactly on their 95th birthday?)
4. Any retirement planning should take into account that you could end up with way more, or way less money that you thought.
(Sadly, the web app was never released by the company.)