"There are special dates, and there are associated traditions.  Christmas  - exchange of gifts, Bonfire night - 'penny for the guy collections', Halloween - nightime bouldering and pumpkin carving competition... it's a tradition gathering momentum, and this year it's happening at Stanage Plantation.  So on All Hallows' Even (Friday 31st October), from 6:30pm onwards, join the gathering of jack-o-lantern carrying night-boulderers, in fancy dress if you wish (you won't be the only one) at either the Business boulder or the Pebble.  There will be a small prize for the best pumpkin, voting will take place in the pub when the witching hour is upon us (or perhaps slightly before then, or the pubs'll all be shut)."

More details at this thread: Annual halloween event - night bouldering & pumpkin competition

and to get you in the mood....