Chrome 32 Beta has a useful feature that lets you launch apps from the Chrome App Launcher without first installing them.
If you are using Chrome 32 Beta and are running Windows or Chrome OS, you'll 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 should be highlighted at the top of the page. Click the Enable link and restart Chrome.
Now, when you open the Chrome App Launcher, for any app that gets returned as a search result, instead of the single Add to Chrome button you'll see two: Add and Launch. Click the Launch button to open the app without installing it.
For more on Chrome 32 Beta, read Seth Rosenblatt's overview.
(Via OMG Chrome)