Why cannot I find a download link for a framework, how can I host a gadget?

You can create a gadget defining an xml spec (reference) and host it anywhere you want (ie. your dropbox public folder). The xml will have a Content section with the html for the gadget. There you can include script tags with any js library you want to use (ie. jquery, dojo, your own js files). If you want to install the gadget in iGoogle, you need to go to 'Add Stuff' and instead from picking a gadget from the directory, you click on 'add rss or gadget' link and enter the url to your gadget xml file. The container (in this case iGoogle, but could be Orkut, MySpace, etc) will pull your gadget spec and render the gadget.