If anybody is used to the // {{ and // }} folding in vim and wants the same in TextMate you can use the following language config to do similar things with Ruby.
#begin ten
=begin
This is inline documentation
=end
def ten
   10
end
#end
The following will create a fold between #begin and #end as well as add a fold for =begin/=end comments.
Add the following two lines to your Ruby language file in the foldingStartMarker section . . . 
            |begin
            |=begin               # line 1
            |[#]begin             # line 2
            |for|while|until
and these two to your foldingEndMarker section . . . 
        |   ^     \s*+ [}\]] \s*+ ([#].*)? $
        |   [#] .*? \(end\) \s*+ $    # Sune's special marker
        |^=end$                         # line 1
        |[#]end$                         # line 2
        )';
Hope this is helpful.
'njoy,
Mark
-- 
Cropp's Law:
        The amount of work done varies inversly with the time spent in the
        office.