Thanks to reader Brian for sending this one in. If you remember (or are curious about) using older Macs, you should check out Infinite Macintosh. You click on the site, give it a few minutes to load in, and it’s just like you’re sitting behind old reliable one more time.
They are all fun, but I found the System 6 emulator to be my biggest time suck. I particularly enjoyed the small touches, like how you need to hold down the mouse button on menus, just as the classic Macs required. I’d definitely recommend putting off clicking the above links until you’ve got some free time on your hands.