I'm having a problem running the default task with RakeMate.  Rake reports an error saying that '(default task)' is not a valid task.  I worked around the problem by converting the 'task' variable returned by TextMate:: UI.request_item to a string on line 58 of rake_mate.rb:

  task = task.to_s

Apparently request_item is return an Array, so 'task == DEFAULT_TASK' returns false.  Converting task to a string fixes it.  I'm using TextMate 1383, which is the latest cutting edge I believe.