Dorothy Mengering
Following several years of appearing via telephone , Mengering ( usually billed as "Dave's Mom" or "Dave's Mom Dorothy" , with no mention of her surname ) became a recurring on-camera guest on Letterman's subsequent "Late Show" , initially by covering the 1994 Winter Olympics in Lillehammer , Norway . 
<triplet> 1994 Winter Olympics <subj> 1994 <obj> point in time <subj> Norway <obj> country <triplet> Lillehammer <subj> Norway <obj> country