Thanks for the responses

The reason that I need to soundproof is that I have a
sleep disorder called night terrors where I scream in
my sleep. I feel really bad about disturbing my
neighbors.

That's a good point about how blocking different types of
noise requires different solutions. I was hoping that I
could concentrate on the sheer loudness first and that the fine
points like noise frequency would be my second effort if
necessary.

I know that the sounds penetrate the walls, but the large window
is probably the primary issue.

Jim's suggest of foam board is intriguing. It would definitely
provide insulation from heat-cold. As he mentioned, it's light.
And it's probably reasonably priced.

Joseph's suggestion of acoustical foam is interesting since
I've never heard of this. I'll research. The web sites that
discuss soundproof insulation are often sales pitches and not
economical solutions.

The suggestion to do something to the outside got me
thinking about shutters.

I appreciate the warning about acoustical fiberglass
insulation which I've never heard of.

Michelle, getting my materials cut at the store whenever
possible should work great for me. When I fold down the
back seats in my compact, I get more than 5 feet of length
for materials.

Hopefully, I'll be able to reuse my window plug materials
when I move.

You might be amused by my other ideas.

o Taping my mouth shut so that I'd awake if I try to
talk. (You can laugh, but there are multiple discussions
on another (asthma?) newsgroup that eventually reject this
idea as too dangerous.)

o Soundproofing a large closet and sleeping on a cot
or an inflatable mattress

o Building somethink like a soundproof coffin. Rejected
because I don't like enclosed spaces and probably too
costly

o Building a soundproof head mask. Also rejected
but not because I have anything against medieval themes

Yes, I am a little desperate.