Chrome 32, which is the latest version and is now on your computer if you're using Chrome, has a useful feature that lets you launch apps from the Chrome App Launcher without first installing them. You simply need to enable the experimental ephemeral apps flag to use this feature. To do so, head to this page:
The "Enable experimental ephemeral apps" line might be highlighted at the top of the page but, if not, type "ephemeral" into the Find box (click on the Customize button at the top right of Chrome to bring up the Find). Click the Enable link and restart Chrome.