Copy and paste the bookmarklet code into your bookmarks. Open the bookmark to activate.
If you want to use a bookmark on secure websites like Facebook or Gmail, you must use the source code available above (prepended with javascript:).

View a website in 3D layers.

javascript:(function(){var js=document.body.appendChild(document.createElement("script"));js.onerror=function(){alert("Sorry, the script could not be loaded.")};js.src="https://rawgit.com/Krazete/bookmarklets/master/3D.js"})();

After activating, view the menu in the top left corner.

Add a piano to any website.

javascript:(function(){var js=document.body.appendChild(document.createElement("script"));js.onerror=function(){alert("Sorry, the script could not be loaded.")};js.src="https://rawgit.com/Krazete/bookmarklets/master/piano.js"})();

Control the wave type, octave level, and axis tilt in the left menu.

• can also control octave level with left and right keyboard arrows
• can also control tilt with up and down keyboard arrows

Control playback in the right menu.

• "# ▶" is a play button
• "# ◼" is a stop button
• "↻ #" is the history playback button
• "✖" is to delete a disc or clear history
  • can also clear history with spacebar
• "⬇" is to save history as a a disc
• "⬆︎" is to export all saved discs
  • only useful with a local copy of the full code

A game of ultimate tic-tac-toe.

javascript:(function(){var js=document.body.appendChild(document.createElement("script"));js.onerror=function(){alert("Sorry, the script could not be loaded.")};js.src="https://rawgit.com/Krazete/bookmarklets/master/tic.js"})();

The rules are explained here.

A replicated Lumosity game.

javascript:(function(){var js=document.body.appendChild(document.createElement("script"));js.onerror=function(){alert("Sorry, the script could not be loaded.")};js.src="https://rawgit.com/Krazete/bookmarklets/master/lupire.js"})();

See Lumosity's pinball recall game.

Watch a video and read comments simultaneously.

javascript:(function(){document.body.appendChild(document.createElement("script")).src="https://rawgit.com/Krazete/bookmarklets/master/ytscroller.js"})();

Active this bookmarklet upon first loading YouTube.
You can also use the source code with a userscript app like TamperMonkey to make this automatic.

Check multiple videos' like statuses all at once (to avoid clickbait and such).

javascript:(function(){document.body.appendChild(document.createElement("script")).src="https://rawgit.com/Krazete/bookmarklets/master/ytsentiment.js"})();

Activate this bookmarklet on any YouTube page with multiple video links.

• green: #(likes) > #(dislikes)
• murky green: #(likes) == #(dislikes)
• red: #(likes) < #(dislikes)