What to do....

DH and I want to take DS1 to do something special just the three of us. Ds2 sucks up so much of our time and attention and DD gets to do fun stuff with every body else all the time. So we were thinking about bringing him to Global wild life but we are hesitant about it. DS1 is going through this stage were he is afraid of everything right now. Bugs, noises, you name it. So Having a giraffe come up to him and lick him might not be his idea of fun lol. IDK we are really torn at this point as to what to do. We took all the kids to the zoo and aquarium not that long ago. And he is only 21 months old so we can't take him to a movie or any thing. HELP! What should we do?