With the newest version of Screenlets, 0.1, you can now run not only Python Screenlets but also Google Gadgets, other web widgets, and web applications. If you want to get started with Screenlets, I’ve previously written a guide about installing and configuring it: OS X-Like Widgets with Screenlets on Ubuntu.
Start the Screenlets Manager (Applications->Accessories->Screenlets). If you get an error about Gtkmozembed, you need to fix this first by installing the python-gnome2-extras package:
sudo apt-get install python-gnome2-extras