GRP ... is a code name for   GUINNESS RECORD PROJECT The previous Guinness World Record for the most DIFFERENT roller coasters ridden within a continuous 24 hour period was 29... We  SHATTERED  that record by riding  40 COASTERS  in 23.5 hours...!! This project was in the planning stages for many months... Starting at 5:00pm on Saturday October 14th, 2000, FOURTEEN members of  American Coaster Enthusiasts  traveled to EIGHT California parks... It was grueling... and dramatic... and difficult.... ...and it was all recorded for a one-hour prime time Discovery Channel special which aired on May 28th, 2001...!