Summer Holidays Fun Ideas?

Right well i know its June and i cannot wait for summer (il be 15 in the summer) and my parents are leaving the country with my sister (thank god) and im staying with some relatives i havent seen in years (My grandad, Step Grandma and Two Step Aunts) and tbh they dont care what i do :L so does any one have any ideas on what i could put on my summer bucket list of things to do? i want this summer to be remembered as the bestest one EVER :) (btw theres no beaches around, il be in Alum Rock, Birmingham)