There's a github repo trying to rewrite it for the web: https://github.com/jackinloadup/lunatic-fringe

There's also this, which I vaguely remember working for me years ago, but can't vouch for now: http://www.sealiesoftware.com/fringe/

I have incredibly fond memories of playing Lunatic Fringe, despite being very bad at it, and despite catching a ridiculously bad case of strep throat one year shortly after discovering it, and having some bad, vaguely-related fever dreams about.

Man, playing games in After Dark was so annoying... accidentally move the mouse and lose all your progress. ("Rodger Dodger" was my own favorite.) I guess the thing to do would be to get ahold of the "After Dark Games" CD... I'm sure there's got to be some way to play that still...

Edit: Looking it up, the After Dark Games version of Rodger Dodger apparently has different levels from the screensaver version! (And not just in that it added ones; in fact it has fewer in total.) That's annoying...

I haven't tried this since the PPC days:

http://sealiesoftware.com/fringe/

Ben Haller still maintains a version of Satori and Rose for Mac OS X:

http://www.sticksoftware.com