An old-timer like you might be interested in knowing that several "old favorites" now have OS X versions, such as Conan the Librarian X and
(And with OS X you can install these dumb apps without worrying whether much if they'll make your Mac unstable.)
For additional quirkiness, you'll need custom icons for every file and folder on your hard disk:
And good desktop pictures corrected for your gamma:
Remember, free Java/Shockwave games run fine on OS X, even if they claim not to:
Eventually, of course, you'll have to get back to Web development.
If you really want to fiddle around with stuff, may I suggest tinkering around the the Terminal?
Installing MySQL: [entropy.ch ]
PHP: [entropy.ch ]
Apache 2 [laughingmeme.org ]
If you use Perl DBD::MySQL, watch out for this one:
Hope that's enough to keep you busy for a bit. :)