With the caveat that liquid will leak out of the punctured areas and get
all over the microwave tray :-)  

http://www.fabulousfoods.com/features/featuring/spagsquash.html

How To Cook Spaghetti Squash

    •     Bake It -- Pierce the whole shell several times with a large fork or
skewer and place in baking dish. Cook squash in preheated 375°F oven
approximately 1 hour or until flesh is tender.

    •     Boil It -- Heat a pot of water large enough to hold the whole
squash. When the water is boiling, drop in the squash and cook for 20 to
30 minutes, depending on its size. When a fork goes easily into the
flesh, the squash is done.

    •     Microwave It -- Cut squash in half lengthwise; remove seeds. Place
squash cut sides up in a microwave dish with 1/4 cup water. Cover with
plastic wrap and cook on high for 10 to 12 minutes, depending on size of
squash. Add more cooking time if necessary. Let stand covered, for 5
minutes. With fork "comb" out the strands.

    •     Slow Cooker or Crock-Pot - Choose a smaller spaghetti squash
(unless you have an extra large slow cooker) so that it will fit. Add 2
cups of water to slow cooker. Pierce the whole shell several times with
a large fork or skewer, add to Crock Pot, cover and cook on low for 8 to
9 hours.

 Once the squash is cooked, let it cool for 10 to 20 minutes so it will
be easier to handle, before cutting in half (if it wasn't already) and
removing the seeds. Pull a fork lengthwise through the flesh to separate
it into long strands.  You can do these steps ahead of time, then
prepare any of the spaghetti squash recipes whenever the mood strikes.

Jennifer

   We have it quite often, and have tried baking, nuking, and boiling.
Generally, it all comes out pretty much the same, like you say. It doesn't
taste like spaghetti at all, but it goes great with a meat sauce and has
it's own likeable flavour.

I have a REALLY hard time slicing spaghetti squash when it's raw, so
puncturing it and cooking it until I CAN easily cut it open works well
for me.