By now, you know such a thing has never happened in NBA history, but it turns out it's rare in all four major American sports. In fact, only three times has the same college had players selected No. 1 and No. 2 in the same draft.
It's never happened in the NBA, MLB and NHL, and hasn't happened in the NFL since 2000, when Courtney Brown and LaVar Arrington were taken first and second overall out of Penn State. It also happened in 1984 (Irving Fryar and Dean Steinkuhler from Nebraska) and 1967 (Bubba Smith and Clint Jones from Michigan State).
Taking things a step further, it's only the fifth time two teammates have been selected at the top of a draft. In the NHL, where players are drafted from amateur club teams more often than colleges, teammates from Canadian club teams were taken first in second in 1969 (Rejean Houle and Marc Tardif from the Montreal Junior Canadiens) and 1963 (Garry Monahan and Pete Mahovlich from the St. Michael's Juveniles).
I bet you didn't expect to read about Canadian junior hockey today, did you?