I was just gonna suggest decorating the house while he's out, turning the lights low, possibly getting into something sexy, getting a cake, and both you guys just bumming it with netflix/games. As for gift ideas it depends on how much you're willing to spend, You could get him an album he doesn't own for a band/group/artist he likes, a game he wants but doesn't have, (if you've got money) a lens for his camera or a new camera, etc.