I was also wondering is there was any science museum or "learn-a-torium" for kids that might have a periodic table display, with purified samples and/or ores setup. Of course, Woelen:'s page does the gasses right -- no point in showing tubes that might as well contain air, but instead send a current through and show all the colors possible. But someone, with adequate shielding, should show us what we can get with a radon lamp, as an example.