A 17-year-old has definite tastes and preferences, so if you are planning a party for him, talk with him about what he wants it to be like. If it's a surprise, plan it with his best friends, since together you can better throw a party that feels mature enough for a 17-year-old but follows your own rules as well. Your teen will appreciate the extra effort.
If you have a pool, you already have the perfect setting for a warm-weather party. If not, arrange to hold the party at a public pool or a friend's house. Or, have a barbecue party in the backyard, with sprinklers to cool people off.
Likewise, in warm weather, a camp-out is lots of fun for a nature-loving teen. And it saves you the trouble of cleaning the house before and after the party. Hold it at a nearby state or national park, telling the guests to bring their own tents or arrange to share.
Put a spin on the traditional costume party, having guests create their own costumes but not for themselves. Tell them to each bring a costume for someone else to wear. Give each costume a number, and write the same number on a small piece of paper. Have each guest draw a number to find out which costume she'll wear. Or have everyone bring random clothing and accessories, the stranger the better, and try to assemble outfits from them. Then, have them all go somewhere in public together. If it's a small group, go to a movie or to get a pizza. Everyone will have a great time laughing about the stares they get.
Likewise, a Mardi Gras party will be a big hit with teens. Have everyone wear masks and colored beads. If your teen's friends are crafty, bring plain masks and decorating supplies to the party so they can decorate masks together. Serve spicy Cajun food and play fun carnival music as guests arrive, as Party411 suggests.
A game night is also a great low-key party idea for a smaller group. Gather classic party games like Twister and Taboo, and spread lots of beanbags or cushions around the room to turn it into a comfy lounge area. Set out bowls of snacks and drinks, play your teen's favorite music, and give the guests space to do their own thing.
Family and Friends Dinner
Taking your teen to dinner with a group of family and friends is also a great way to celebrate a birthday. Or, have a dinner at home, making your teen's favorite meal. This is a great way to enjoy family time and remind your teen how proud you are of her. If she wants a bigger party, schedule it for the next day so you won't feel rushed or overwhelmed.
Set clear rules beforehand so your teen does not assume the rules have changed because he's older. For instance, tell him how many friends are allowed to stay over, and that they must be boys (or vice versa for girls). Give a little leeway regarding the number of kids who can stay over, if only a small group remains by the end of the party, so your teen doesn't have to pick and choose who stays and goes. Give them space, but drop in with drinks or snacks if you feel you need to check on them.