If you want a cliffhanger experience out here in Sikkim, Gangtok perimeter offers some prime spots. There are some terrific, dizzying places for those who get their kicks from crawling up vertical cliffs. If you are not making it to high peaks, here's another opportunity to get a high.
Of late, rock climbing has found increasing popularity among the tourists coming into Sikkim as well as for local enthusiasts. Trekking agencies too have jumped into the bandwagon and some of them now offer the rock climbing experience.
Your rock climbing trip can therefore be combined with bird watching and experiencing some of the last of the Sikkim wilds.