This web page is the very simple UI for a very simple REST API that I like to use for demos and training.

The idea is simple:
Trendsetter lets you set trends. That is, you get to decide what's trendy, and when. Are bell-bottoms due for a comeback? Is the handlebar mustache fad over? Has Crystal Pepsi become so retro that it's cool now? The decision is all yours

There's just one rule:
Once something's trendy, it can't be trendy again for 10 years. So you'll have to wait just a little bit longer before resurrecting MySpace.