Similar movie

Does anyone know the name of this one movie similar to this one. I saw it on HBO in '97, so I remember it being from 95 or 96. It's a comedy about two guys and a girl, all aabout college age,on a road trip to Mexico. Unknowingly they had been traveling with a severed head. To the best of my knowledge nobody famous is in it unless someone brokeout after this particular movie. If anyone can help me with this one I would be very thankful.