It may sound paradoxical, but sometimes the best way to show your friend you care is to pick on her a little. Have fun with a buddy, family member or significant other with a sense of humour on her 18th birthday by doling out a little bit of good-natured embarrassment.
What's more embarrassing for the birthday boy than being hauled out of bed in his pyjamas? Talk to the guest of honor's parents ahead of time and arrange for them to leave the door open or let you into the house before he wakes up. Go into birthday boy's room wake him up and "kidnap" him by hustling him out of the house with bed hair in whatever he happens to be wearing. (You may want to let him put on something if he happens to sleep in his underwear.) Take him out to breakfast at a local pancake house or other breakfast joint. Afterwards, take him to a bowling alley, movie, pool hall or whatever sort of place he likes to hang out.
Baby Pictures Birthday
If you are the parent of a kid who is turning 18 and have some baby pictures around, embarrass her with a baby birthday. Find some way to get her out of the house for a few hours and, while she is gone, put up blowups of her baby pictures all over the house. Set up slideshows or computer monitors and TV screens. Be sure to include those toddler photos where she has chocolate birthday frosting all over her little face and other unflattering shots. Have all of her friends come over just before she gets home and have them sign a kid photo of her. Tell her friends all of your favourite embarrassing stories. Better yet, bring out the old home movies. She'll be simultaneously charmed and mortified.
Throw your friend a deliberately childish birthday when he turns 18. For example, you could hold a cowboys-and-Indians party. Hand out cap guns, fake bows and arrows and feather headdresses and paint his face with war paint. Hire a kids cowboy entertainer to do rope tricks or rent a pony for pony rides. Alternately, you could do a standard kids birthday with a clown or a magician, pin-the-tail-on-the-donkey and all of the other classic little-kids'-party activities.