Unity 3D is a free, and quite simple to use program for making 3-D videogames (and also 2-D, but you may be better looking elsewhere). It's easy to find help, and to avoid scripting by using our search engine of choice, and a lot of basic things are taken care of for you (physics, for example). With a copy og the program and an open Internet browser you should be able to have your first 3-D thing running in an hour or less.
The free version of Unity can export to Windows, Linux, and Mac OS (all in 32-bit and/or 64-bit varieties), and well as to the Unity web player, which with the downloading of a plugin lets people play your games in their browser (by hosting it on Dropbox, your own webspace, etc.). The HTML file this generates can be completely changed, it's just there for convenience.