Classic mac emulation in your browser (infinitemac.org)
This site allows you to experience what classic Macintosh operating systems were like. You can launch most of those versions in your browser. More applications and games can be installed as well. At the very least, you can see how the operating system evolved over time.
Infinite Mac: Classic Macs running in the browser (infinitemac.org)
Infinite Mac is a collection of classic Macintosh system releases and software, all easily accessible from the comfort of a web browser.
Infinite Mac - A Classic MacOS Emulator In Your Browser (infinitemac.org)
Seems like a pretty cool toy. They've got tons of software