One option is Decker: http://beyondloom.com/decker/ http://beyondloom.com/decker/ Aesthetically, very similar to classic HyperCard. Simple to use, highly porta

One option is Decker: http://beyondloom.com/decker/ http://beyondloom.com/decker/ Aesthetically, very similar to classic HyperCard. Simple to use, highly portable, completely open-source with no strings attached and no expiration date. It uses a very different scripting language (APL-like rather than xTalk). For fidelity between the native application and the browser-based port, certain features are constrained or missing relative to HyperCard- no analog to XCMDs, for example- but then again it's FOSS, so anyone can hack in new functionality if they have some familiarity with JS or C.