The coolest toy environment is Konfabulator – Widget Workshop. This allows you to make widgets in xml and javascript for your Mac OS X. The little widgets are toy programs that do something simple like an analogue clock or a to do list.
In effect Konfabulator provides something like HyperCard for OS X. A simple graphical programming environment. It can interface with other things. It has a skins feel (in fact it was created by the team that created a skins tool for earlier versions of the Mac.)
Very cool. Now, can I use it to create an interface to Ruby tools.