This is a really simple screensaver that I've wanted to have for a long time
http://octavoarte.cl/intruderalert.scr
I wound up checking for input and terminating myself, as the screensaver option would export something that crashed on start. So that explains the weird name in Windows panel.
This was exported as .exe, icon-hacked and then renamed to .scr
I have a feeling I might have gone overboard with the textures. Let me know if it works for you.
Edit: textures halved in size. Sound stops at one minute, so people won't kill you if you use it.