some people - me for example - may find hiking quite dull. You need a good mix of activities and with the option for some people to not take part if they feel intimidated. For example, the old aunty might not feel comfortable playing volleyball but would have fun cheering from sidelines.
failing that, take trebor's advice. best team building I ever did in HK was an afternoon/evening in the pub on the company's tab. wasn't chea p though/