Thanks to both of you (CHubas and Robert).  I didn't see the replies
because either I don't get replies to my threads e-mailed to me or I'm
just oblivious.

I've written a few things myself, things on the order of
Range#contains?, Range#contained_by?, Range#overlaps?.  The real
trick, however comes when I'm using extensions built on top of Range,
extensions that allow a range-ish objects that have open ends.  I'm
not talking about excluding the end, like 1...10, but allowing the
absence of an end, like 1..nil.  Now, that can be done easily enough
with numbers and Infinity (1.0/0), but it gets troublesome when using,
say, Times or Dates.

--
-yossef