Our activities in heaven is going to be all about glorifying God by praising and worshipping his only name. It's going to be wonderful place where God is going to manifest his full glory and we his sons including the saints and angels are all going to remain in awe by constantly exalt him. Heaven according to the book of revelation there is going to be new heaven and earth, where there will be no death because by this time the death bringer i.e, devil will be completely annihilated and thrown into the abyss of hell where him and his minions and cohorts would remain for eternity. In the same vain, old earth would be purged from all form of sins that plagued it by the activities of the devil. And finally the newness that's going to be experienced in heaven will be introduced on earth and then heaven and earth will become one, because there would be no gulf between the both because by then, sins and the wicked will of man would've been subjected to the Holy Will of God Almighty