must say, im jelouse that you get a gazebo. if i got a gazebo then i would chose a couple colors that i like then put a bunch of flowers and veins or something like that around it. but it depends what you want, do you want it a more natural look or.....? anyways, good luck with your birthday!!(:
any way you like. make it match the theme of your party if you have one. maybe you could go simple and not really do anything with it. . .
you should get those lantern lights and hang it in there! like ones like these: http://funadvice.com/r/3k4774q3t7