Behind the Forum and down the stairs, Mac Arena Mar is one of your best party options in summer. The bar is next to an artificial beach and the party just goes on. Especially Sunday afternoons bring out ravers of all ages.
Mac Arena let's you do it your way - if you're skint, pack a bag and sit outside the fence; the PA plays towards the water. If you want to go "inside", there's quite a few sofas, benches and what-not to chill out in; or a dance floor right on the sand.
Get there early for some food; then be ready when the DJs fire up under you.