"You must be older than Harry Potter to be served in this establishment."

"Kid, seriously---I'm going to need to see some ID before I serve you that Butterbeer.  Yes, I see the scar; the scar doesn't have your birthdate on it!"

https://en.wikipedia.org/wiki/The_X-Presidents

https://en.wikipedia.org/wiki/The_Ambiguously_Gay_Duo

Meridian 59

"You must be older than MMORPGs to be served in this establishment."

Shoren begorrah, Batman! What? That's the only Irish thing I know

"You must be older than Angela's Ashes to be served in this establishment."

http://awoiaf.westeros.org/index.php/A_Game_of_Thrones

https://en.wikipedia.org/wiki/Recurring_Saturday_Night_Live_characters_and_sketches_introduced_1995%E2%80%931996#The_Roxbury_Guys

https://en.wikipedia.org/wiki/The_Spartan_Cheerleaders

"You must be older than the Million Man March to be served in this establishment."

"You must be older than To Die For to be served in this establishment."

Jessie Spano / How'd you get so far gone-oh?

"You must be older than Showgirls to be served in this establishment."

I agree with the second part

"You must be older than Se7en to be served in this establishment."

Canadian Bacon

"You must be older than John Candy's last film---and Michael Moore's funniest---to be served in this establishment."

Empire Records

"You must be older than Liv Tyler's cinematic career to be served in this establishment."

... and happy birthday, Brita!  I hope you like this movie---the other ones coming next are decidedly worse birthday messages.

"You must have been born before the New York Times published the Unabomber's manifesto to be served in this establishment."

"You must be older than eBay to be served in this establishment."

"You must be older than the DVD to be served in this establishment."

AKA: The first clue Mick Jagger might not have been as cool as your grandparents always insisted

"You must be older than Windows 95 to drink here."

People were shocked that Kevin Costner was not, in fact, bulletproof

"You must be older than Waterworld to drink here."

No, I don't wanna show it.  

KIDS

"You must be older than Chloe Sevigny's film career.  And Rosario Dawson's.  To be served in this establishment."