Markup is a framework for designing websites easily.

It has a plethora of useful tools — layouts, widgets, typography styles, etc. — to use as a starting point for your very own design.

Markup adheres to the latest HTML5/CSS3 standards and is search-engine friendly. Its layouts are responsive and the framework itself is fully documented.

While you might be tempted to stick to your old guns — jQuery UI components probably — Markup actually looks quite powerful and might be a refreshing change at least.

Dabblet is a nice playground for quickly running HTML and CSS code.

It’s really easy to use and has an extremely useful UI that shows, for example, the color you’re picking at the moment; other nifty features are included as well.

Dabblet uses -prefix-free so no prefixes are required when coding (just make sure your target environment uses it as well) and, sadly, only the most recent versions of Chrome, FireFox and Safari are supported as of now.

Pedestal is an open source toolset for building web applications with Clojure.

Pedestal is made up from Clojure libraries and tools that allow coding in a single language, albeit one not too popular.

Pedestal puts an emphasis on collaboration (it has a shared interface) and scalability, which makes it a good library for larger projects.

Aleo Free Font is a nice typeface designed as a slab serif companion to the Lato font.

Aleo looks sleek and neat. It’s released under the SIL Open Font license, so you can use it in free and commercial projects alike.

The font supports diacritics and has six styles that make for a slick and attractive font for everyday use.

Fool.js is a jQuery library for messing up your website on the 1st of April.

Fool.js has a number of useful features — starting from rickrolling you to making elements disappear and showing videos of Justin Bieber.

While this library means you won’t get points for originality, but at least your users will probably have some fun. Don’t forget to make it disable-able.

iLightBox is a plugin for creating an all-encompassing and feature-rich lightbox.

Among the notable features are:

• Fullscreen, retina-ready skins;
• Swipe event support;
• Supports most devices and browsers (down to IE7);
• Comes with a powerful JavaScript API;
• Keyboard events et al.

You can tweak the plugin like mad and use basically any content you can imagine in the lightboxes. What’s more, it also recognizes video not only from YT/Vimeo, but also from Hulu, MetaCafe, Dailymotion and other websites.