Try ToddlerBot in the browser
Watch the robot move, then move each joint yourself within its real limits: the part it moves lights up. MuJoCo runs in your browser: nothing runs on Robotheca's servers, and no code from the repository runs.
Downloads the creator's MuJoCo files from GitHub (at most 83.9 MB; the URDF's are 67.7 MB), once: your browser keeps them for next time.
Files come from GitHub at commit e337f3b: the creator's MuJoCo scene (toddlerbot/descriptions/toddlerbot_2xc/scene.xml) when it loads, else the URDF. Walking and balancing need the creators' own controllers and are not simulated here.
Model by @hshi74, from hshi74/toddlerbot at commit e337f3b, read from GitHub in your browser. Hardware license: MIT; software license: MIT. The simulation shows how the model moves, not how the real robot will behave.