I come from HKUST, too. You don't need a fitness card to exercise in the gym on the east campus of the school. Just show him your one-card card. You can use the fitness equipment inside for free.

If you swim in the swimming pool in the South District, you must get a card. It seems to be ten yuan (I did it when I was a freshman, but I don't know the price now). And the badminton hall in the southern district also needs a card. Students at school should punch in if they want to play (one card can make holes, and one card can make 20 holes). The swimming pool and badminton hall in the southern district are open to the public.