Yo Saab! I too can type the administrator password (though it's not called Administrator on my machines).
RunAs is fine if it's a solo machine, but many games store user info and game score in the currently logged on profile - not all of them create an internal database of players. If you have several kids doing games then all the preferences and scores get all mixed up.
And running anything "as" Administrator means that everything gets written into the Administrators document folder rather than yours.
Using Michael Howard's DropMyRights for Internet facing apps. is an approach that appeals to me more and I started using it a while ago. That way you can have two shortcuts for an app. - one with admin privileges and one restricted.
Vista

if it ever ships will supposedly correct these problems but I'm not planning on going there. SuSe 10.1 keeps me pretty happy.
But perhaps I should reconsider RunAs as a strategy on the Windows machines - I'll try demoting Tom and see how many of his games crash out, I forsee some tears ahead!