Over the years, ActionController::Base#render has grown quite a few options:

[sourcecode language='ruby']
render :action => "edit"
render :template => "products/show"
render :file => "/u/apps/other/warning.html"
render :nothing => true
render :inline => "<% @product.name %>"
render :update {|p| p.replace_html "A", "Error!"}
render :text => "OK"
render :json => @product
render :xml => @product
render :js => "alert('error!');"
[/sourcecode]

Those options will still be in Rails 2.3, but the first three have a simpler alternative now:

[sourcecode language='ruby']
render "edit"
render "products/show"
render "/u/apps/other/warning.html"
[/sourcecode]

Rails will figure out whether you're rendering an action, template, or file, and do the right thing. In addition, if you like symbols, you can render an action via a symbol:

[sourcecode language='ruby']
render :edit
[/sourcecode]