Sorry, ignore the "additional information" that says both versions 0.7.11 and 0.7.12 are installed.  By the time 
the screenshot was taken, only 0.7.12 was installed.

Hmm, I remember that Ruby installations on Tiger sometimes were a bit quirky with both the standard Ruby 
and another one being installed. Did you change anything about your Ruby installations between 0.7.11 and 
0.7.12? In any case it would be helpful to know if the packaged Gosu from the Downloads page works, you 
can verify this i.e. by going into it's examples folder and running:
/usr/bin/ruby -r'../lib/gosu' Tutorial.rb

Same problem with the standalone package (in addition to some library issues).

I started by uninstalling the gem version of gosu.

Then I checked the local ruby install:

io:~ greg$ which ruby
/usr/local/bin/ruby
io:~ greg$ ruby --version
ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-darwin8.11.1]
io:~ greg$ /usr/bin/ruby --version
ruby 1.8.2 (2004-12-25) [universal-darwin8.0]

Then, I downloaded the "gosu-mac-0.7.12.tar.gz" file (using Safari) and expanded with "gnutar zxf gosu-mac-0.7.12.tar.gz"

Tried to run examples/Tutorial.rb:

Started with copy & paste from your comment:

io:~/Documents/Downloads/gosu/examples greg$ /usr/bin/ruby -r'../lib/gosu' Tutorial.rb 
Tutorial.rb:8:in `require': No such file to load -- gosu (LoadError)
        from Tutorial.rb:8

Next, tried putting in the actual filename:

io:~/Documents/Downloads/gosu/examples greg$ /usr/bin/ruby -r'../lib/gosu.bundle' Tutorial.rb 
Tutorial.rb:8:in `require': No such file to load -- gosu (LoadError)
        from Tutorial.rb:8

Then, I got lazy and cheated:
io:~/Documents/Downloads/gosu/examples greg$ cp ../lib/gosu.bundle ./
io:~/Documents/Downloads/gosu/examples greg$ /usr/bin/ruby Tutorial.rb 

That found the library and executed the Tutorial.  However, I still got the 42-second pause while displaying the last image 
that had been previously displayed in a gosu window.
After the pause, the game worked perfectly.

Also note that /usr/local/bin/ruby also has the same pause effect as /usr/bin/ruby.

Huh, weirdest bug I've seen in a LONG time :) Thanks for testing! Could run the following script too, that has 
some more printf() style debugging to narrow down which part of Gosu got slower: 
http://www.raschke.de/julian/temp/TutWithTimestamps.rb
After that, I'll go through the whole changelog between 0.7.11 and 0.7.12 to look for something that could 
cause that.

Well, I don't know if this is good or bad, but it's none of those.  :)  All the checkpoints you placed in the file run (nearly) 
instantly, as you'll see from the attached file 'timestamp.log'.  I modified the TutWithTimestamps.rb file (also attached) to log 
various actions, and from there you'll see that the first update() doesn't run until 43 seconds after initialize finishes.

	TutWithTimestamps.rb
	3.3 KB Download

	timestamp.log
	2.5 KB Download

Phew. Just finished reading through the complete svn diff and still no idea what's causing such a constant 
delay. I uploaded a recent build of Ruby/Gosu here: http://www.raschke.de/julian/temp/gosu.bundle, in 
case it's some sort of obscure bug in the Ruby/Gosu wrapping (I've updated the version of SWIG I use for 
packaging since releasing 0.7.11).

As a last resort, I'd suggest filling the RubyGosu Deployment Template with the tutorial data: just copy over 
the Tutorial.rb file and the media folder to the Resources subfolder, and rename Tutorial.rb to Main.rb. You 
may also throw in the recent gosu.bundle. Then, you can create a CPU usage profile using Shark (from 
Xcode) if the delay is still there.

(Sorry about the delay--work's been crazy)

Downloaded the new bundle, still saw the pause.

Created the Mac OS X deployable app with the new bundle, still saw the pause.

I've never really used Shark before, so let me know if there is a custom report you want me to run.  I ran the default Time Profile - Everything, 
set to gather for 60 seconds, starting before the app is run and finishing after the game begins responding.

Unfortunately, the mshark file is ~8.7MB, so it doesn't seem to want to attach to this comment.  You can grab it (slowly) from:
http://io.tresghic.com/gosu/Time_Profile_Everything.mshark

I also grabbed another screenshot to show a new pattern that was displayed in the window while the game was blocked.  Mostly, it was bright, 
so it got my attention.  :)  http://io.tresghic.com/gosu/tutorial_app_during_lock.png

Do you know if anyone else has duplicated this behavior, or is it limited to my system?

Got the mshark file, you can take it down again, thanks!

In the kernel process, there are two functions with unknown names, one using 43.3% of the time and the 
other one using 26.2%. And 69% of a minute are … 41.4 seconds :)

Both functions come from the library com.apple.driver.AppleIntelCPUPowerManagement, so I think I'll look 
for an Apple mailing list that will be able to help out with that.

You are the only one who reported this bug, but it might be that it happens on all Mac Pros with the same 
spec. And I think the gibberish on the hanging Gosu::Window is whatever was in that part of the video 
memory before Gosu started :)

I'll let you know when I get an explanation of the pause from somewhere!