Arizona graveyard

Over here in Europe,we often see pictures of obsolete airliners sitting out their time in the dessert. May I ask,..What happens to all these?. I presume they flew in,and therefore must have been CAA certified at the time. Have you any stories of ones that 'got away' . In 2004/5 a large group of family/friends had to turn up for a wedding in Melbourne. While we were there,we had a tot up of costs to arrive,and decided that it would have been cheaper to rent the whole airplane,than buy individual seats. Another wag,possibly me,suggested it could be even more cost effective if we bought the aircraft,and then sold it after the event. ???