Gtk+ 3.2 will let you run any application in a browser thanks to the new HTML5 gdk backend. That means you'll be able to run GIMP, Gedit, a video editor or whatever, remotely (or on the same computer), using a web browser.
This is still work in progress so not everything works yet (the keyboard input support, dnd or c&p) and also, it only works in Firefox 4 for now, but this is nevertheless amazing.
Check out the following video recorded by Alexander Larsson:
(video also available in WebM)
For more info, visit Alexander Larsson's post.