Order a tall, iced chocolate chai tea with two pumps of Irish creme and a splash of half & half.
I barista so I got bored at work today. Made up my own off-menu drink. Came out really nice; normally Irish creme and chai are potent flavors so the ice, milk and half & half dilute the flavors enough for them to blend nicely together. If you're one of those people who likes having whipped cream, have them do a chocolate drizzle over the whipped cream.
The amount of Irish creme scales by size. So tall is two pumps, grande is four and venti is six. The barista will know how to scale the rest of the stuff on their own.