regex101 : Free PCRE-based regular expression debugger with real time explanation, error detection and highlighting.
Explorer Exposed! : These CSS bugs are all found only in Internet Explorer, versions 5 and higher. To see the demos properly, they must be viewed in IE, of course.
Linked Data : This site exists to provide a home for, or pointers to, resources from across the Linked Data community.
Go by Example : Go by Example is a hands-on introduction to Go using annotated example programs.