Hi,
My bedroom has always been incredibly warm. To make matters worse, it
has been over 100 degrees in my city during the last week. I live in a
two-story house. My bedroom is upstairs and has a vaulted ceiling. I
do have a ceiling fan (and it is set properly for summertime
operation). Even with the fan running at full speed, my room is still
very warm. The air conditioning units for the house are both working
properly, and the rest of the house gets quite cool...there's a
noticible temperature drop the instant I step out of my room and into
the hallway.
Is there any way to get my room cooled down?

Have you thought of buying a small, energy-efficient window air
conditioner for this room?

window fan would help a lot

how much electrical load are you running in the room --
computers? big monitors?  halogen lamps?

You say it is cool outside your bedroom. How about a fan blowing into
your bedroom. Or, you could put in a window fan exhausting air from
your bedroom and pulling in cooler air.

A window unit is not an option in my room. The windows are the wrong
size, and my computer desk sits by the window (no other place to have
it).

Does your house use a forced-air central heating/cooling system? If
so, go to Home Depot and buy a supplemental air-flow fan/booster that
replaces the register (the metal or plastic grille over top of the
duct opening), and helps "suck" air into the room. Since your room is
at the top of the house, you're at "the end of the line" in terms of
getting air-flow from the central air unit. With this booster, it'll
help some.

I can't find it on HD's webstore, but I have seen one in their stores
before. I remember it distinctly, because I found it the week after I
built my own using a 120 VAC muffin fan and some wood.

You are no so bad off, my city Melbourne,( the cold part of Australia)
in the grip of a fierce winter had zero degrees (32 farenheit) showing
on big city thermomenter last night at 2am, the coldest night for some
years I suspect.