this is a great (free) publication that lists loads of outdoor events and acitivies for adults, families and children. Included are several events in the Queens Park, plus a "Seashore Search" on 26 June, which is at Joppa Rocks.
There are plenty of things to do, from bird watching, clearing nature reserves, walks and cylce rides.
As I said, it's free and is a great way of finding out more about the local area. More on www.outdoor-diary.info