Retrogithub.com
Someone simulated a Commodore 64 pin by pin, so you can break it on purpose
A developer who goes by antirez put c64-hw-sim on GitHub, and it simulates the Commodore 64's motherboard pin by pin.
Tag
emulation
Retromacrumors.com
Apple's cancelled future now opens in a browser
Apple cancelled Copland in August 1996, and you can now boot it in a browser tab.
Retro0x3.jawncon.org
JawnCon put its conference schedule inside an emulated Macintosh Plus
JawnCon, Philadelphia's hacker conference, built this year's schedule as a HyperCard stack and runs it "in a Macintosh Plus, in a 68k emulator in your browser," according to the event's schedule page, though a plain web version is there too for anyone in a hurry.
Retrogithub.com
You can play PS2 games in a browser now, recompiled from the original code
PlayStation 2 games are running in a web browser, no emulator attached.