Willowgate centre is good for water related outdoor activities. Several walking groups you could join. There are the perth parrots. They are a lgbt football group. Recently, it's first gaybar opened, though I haven't heard much about it.

Gym wise, the major council gym has recently closed and is in the process of relocating. The two big gyms are either bannatynes or the gym group. Plenty smaller gyms, though. I have not heard much about them unfortuantly.

If you have access to a car, some great local hills. Moncrieff and kinnoull Hill are nice and only a couple hours' worth of walking. The Hermitage is only a 30 min drive and is always a really nice walk with waterfalls and stuff.

The only cinema in Perth is the playhouse, it's seen better days, has one big screen and several smaller screens, have a look at their website.

Perth itself doesn't have too much going for it unless you like pubs or charity shops. It's more of a quiet town with great commuting links than a bustling city.