I was a little paranoid about traveling with high speed film and was researching this last week. From what I was able to see, an Xray machine will basically just fog the film, occasionally it may cast a white or colored band. to get this effect at home I'd say use spent developer, improperly stored and expired film, leave film on a sunny windowsill or in a hot car for a long time or push the film alot. I've also gotten these various "effects" by using the cheapest and crappiest film processing place I could find (I would recommend a drug store that doesn't see much traffic).
