What is the most expensive rave flyer that there is?

We have just sold a Dreamscape 1 flyer in mint condition for £25 equalling a Fantazia Club Tour at the Barrowlands flyer that we sold some time ago.  Generally flyers don't sell in very large amounts but it is undoubted that some have a special place in peoples hearts and that some just really are very rare compared to others.  We printed 1 million flyers for the Fantazia One Step Beyond event in 1992 (the biggest event of ours by some way) and yet they are still very collectable which means rarity is not everything in the price as with that many floating around it just can't be as rare as other event flyers that where only printed in the 000's.

What is the rarest flyer you know about? Which would you love for your rave flyer collection and why?  Did you go to the event or just love it as a form of artwork?