Few birthdays are as significant in a man's life as his 18th. Once a child turns 18, he is both legally and culturally no longer a boy, but a young man, with all the rights and responsibilities that adulthood entails. This change is often celebrated with a no-holds-barred birthday party, one that can take many different forms.

Throw the birthday boy a party at an amusement park, where he can ride roller-coasters and play carnival games in the company of his best friends. Make sure to call the park ahead of time, as many places offer special discounts for large groups.

At a memories party, a boy's best friends and family gather together and tell stories about his time as a child. Often these stories are supplemented with props, such as a photo album or toys from when he was younger. The evening should be a healthy mixture of laughter and tears.

At a barbecue party, the boy's friends fire up a grill and throw on their favorite cuts of meat. A great party to hold on the beach or in an outdoor setting, these festivities can include a bonfire, Frisbee and, if you throw the fete by the beach or a pool, swimming.

Not all nightclubs are restricted to those who can legally drink. At 18+ nightclubs, people 18 and older are allowed in. Sometimes the clubs serve alcohol but card at the bar, while others are dry. Dress to paint the town red and take the birthday boy out for an evening of glitz.

Sometimes, the best parties are the simplest ones. At a restaurant party, a large group of the boy's friends and families reserve a long table or a back room at his favorite restaurant. It's traditional for toasts to be said at these meals and for the birthday boy to make a speech.

For karaoke-themed parties, which are best for smaller groups, the birthday boy and his closest friends hit a karaoke bar and take turns singing pop songs, both new and classic. Have the birthday boy take a crack at the songs he used to love when he was a child.

Perfect for a big group of guys, sports-themed parties usually take place at a park or other location with a large lawn and a baseball diamond. Party-goers play various games, from football to soccer to baseball. Because it's his day, let the birthday boy be team captain and all-time quarterback.