Sims 2 -- Alien Abduction
*Edit* I just got the FreeTime expansion, and it appears that there is an ability for knowledge sims that calls aliens. This should make it much easier to get abducted. This is a video of an alien abduction in The Sims 2. I used the debug cheat to have them abduct my Kairi sim (from modthesims2.com) in broad daylight, during a party.