If the games are stupid and just demanding admin privileges for no good reason, you can force them to run at user-level privileges using http://www.ghacks.net/2010/07/08/get-rid-of-uac-prompts-with-microsofts-application-compatibility-toolkit/.
At work we use an EHR program called OfficeMate. Officially they say it has to be run as admin (but since it's a server-client program that doesn't work http://support.microsoft.com/kb/937624 -- which isn't even documented on their KnowledgeBase). The program, though, runs fine with user privileges. The only reason it seems to demand admin privileges is because they stupidly named one of the files "Wait4SvrInstall.exe" and UAC interprets files with the word "Install" in them as needing admin privileges. Setting it to run as invoker using Compatibility Administrator makes it so I can keep my users from needing admin rights.
If the game is badly coded and actually needs admin rights for some reason, there's no simple fix, but it can be done by http://www.howtogeek.com/howto/windows-vista/create-administrator-mode-shortcuts-without-uac-prompts-in-windows-vista/. (which, IMO, is a pretty bad hack and should be avoided)