Legal: (Adjective) Being the age of consent permitted by law.

Zac "Perfectly Groomed Eyebrows" Efron celebrated his 21st birthday this weekend at L.A.'s Pace restaurant, in the most debauchery-free gathering which included alleged girlfriend Vanessa Hudgens, Ashley Tisdale, Amanda Bynes and Aly and AJ Michalka.

Efron kept it causal in a T-shirt and jacket while Hudgens, 19, who "helped plan the party," a source says, donned a colorful mini-dress. Guests arrived with wrapped gifts, including bottles of liquor for the actor, who can now legally drink alcohol. (Source)

You know what else Zac Efron can legally do now? Butt sex. Of course, he could technically do that before the age of 21... (Now, in all U.S. states!) But, you know, whatever he needs to hear to rationalize it in his head is just fine.

At a photo call for HSM, looking as comfortable and natural standing next to his "girlfriend" as a freshly-neutered cat: