Amazon's Alexa personal assistant is super useful in the Echo and lot of fun to use. But if you don't have an Echo or can't buy one because you're outside of the US or want to use it on your laptop, it can be hard to appreciate Alexa's skill set. In light of this, Amazon has created a web app that lets you play with Alexa right in your browser.
You can access the web app at echosim.io and it lets you ask Alexa all kinds of questions. What it doesn't let you experience is the always listening nature of the Echo device and its far field microphone array — you have to click and hold a button on the site before you speak to it. (That makes it closer to the experience you get with the Amazon Tap than the Echo itself.)
The real purpose of this simulator is to let international devs see what Alexa is capable of, since Amazon doesn't yet sell the Echo or other Alexa devices outside of the US. Amazon says it was inspired by a project from a hackathon last year. Still, it's open to anyone with an Amazon account, so fire it up and start pelting Alexa with questions.