MyOldMac.net has a Flash toy called Web SE that's a great little simulation of System 7 running on the venerable Macintosh SE. Of course, it doesn't do everything your old Mac did, but many of the little details are captured perfectly, like the Eyeballs in the menu bar, the AfterDark Warp screensaver, and classic sounds like "Eep" and "Quack". Web SE includes some apps like MacDraw and MacWrite, plus a handful of classic games, and it even has a simulation of Netscape 3.6 complete with screechy modem sounds.