Midway is apparently releasing some of its earlier titles for free with ad support.
The ads only appear at the games title screen and aren't very intrusive.
Here are the ones that I have found so far.
Area-51 (Alien shoot em up, not bad | Install the patch, major gfx glitches)
http://files.filefront.com/Area+51+Sponsored+by+the+US+Air+Force/;11928815;/fileinfo.html
PSI-OPS (3rd person action)
http://files.filefront.com/Psi+Ops+The+Mindgate+Conspiracy+Full+Client/;10665315;/fileinfo.html
The Suffering: Ties That Bind (3rd person action)
http://files.filefront.com/The+Suffering+Sponsored+by+the+US+Air+Force/;11846564;/fileinfo.html
Supposedly UBI has or had some ad supported free games as well (Far Cry, PoP: The Sands of Time, Splinter Cell); but I haven't really looked for them.
The ads only appear at the games title screen and aren't very intrusive.
Here are the ones that I have found so far.
Area-51 (Alien shoot em up, not bad | Install the patch, major gfx glitches)
http://files.filefront.com/Area+51+Sponsored+by+the+US+Air+Force/;11928815;/fileinfo.html
PSI-OPS (3rd person action)
http://files.filefront.com/Psi+Ops+The+Mindgate+Conspiracy+Full+Client/;10665315;/fileinfo.html
The Suffering: Ties That Bind (3rd person action)
http://files.filefront.com/The+Suffering+Sponsored+by+the+US+Air+Force/;11846564;/fileinfo.html
Supposedly UBI has or had some ad supported free games as well (Far Cry, PoP: The Sands of Time, Splinter Cell); but I haven't really looked for them.