Adobe Air is a technology that allows you to leverage your web development skills and tools to build desktop-enabled applications. Its very slick and gaining traction. Ext is VERY well positioned to be the library of choice for developing these offline apps which require the look and feel of a desktop application.
Adobe has really taken an interest in Ext, even having Jack personally train some of their staff. Adobe has also released a couple of Air applications which use Ext extensively. These apps are available for download and include source code. You can check them out here:
Adobe is also running the Adobe AIR Developer Derby where contestants vie for some awesome prizes by building the most unique Adobe AIR application. The Grand Prize for the Best of Show will receive the trip of a lifetime, a travel certificate valued at up to US$100,000, to be used for the travel of your choice! Other prizes include a Mac Pro 8Core with 4 gigs ram, 1.5 TB (2x750G of storage, Dell LCD monitors, and more.
Again, Ext is very well positioned to develop stunning Air applications so I urge you guys to jump all over this.