SpiffyCorners

The SpiffyCorners widget gives you pure CSS rounded boxes.

The corners are not antialiased, so choose your colors wisely as too much contrast could result in sharp edges.
The CSS technique used has been completely ripped off from: http://www.spiffycorners.com.

How to use it:

<% spiffy_corners :generate_css => true do %>
  I feel rounded!
<% end %>

If you have more than one SpiffyCorners in you page, you need to specify the :generate_css => true option just once, typically on the first one.