Google does some of the most amazingly wonderful things. They have quietly released hosted AJAX Libraries. They are now hosting many of the standard ajax libraries used by developers including my favorite Prototype and Script.aculo.us.
This means all your favorite web applications can refer the same scripts hosted by Google. This will save bandwidth for your hosted web applications and decrease load times for clients as their browser can cache the scripts since they are all from the same Google host.
The API even provides a version specification. So, you don't have to worry about upgrading and managing your Rails versions to get script library upgrades. Just watch your use of the AJAX helpers
It looks like you can use their Javascript API or provide a direct link:
<script src="http://www.google.com/jsapi"></script> google.load("prototype", "1.6.0.2");
http://ajax.googleapis.com/ajax/libs/prototype/1.6.0.2/prototype.js
