Browserling is an interactive cross-browser testing tool inside of your browser built with Node.js. There are a few of these popping up now and if you do any testing its most likely worth the investment if you don't want the VMs running locally or want to show a client away from the office!
![Browserling, cross browser testing from your browser](http://www.andyjarrett.co.uk/blog/images/browserling.png)