This blog's very own Frederick Rhine is the author of today's study (cribbed once again from the terrific HHdbIV).
Chess Life, 2002
White to play and draw
There was a Karpov-Kasparov game in 1991 that reached the pawnless ending KBNN vs. KR. The game was drawn, and subsequent research confirmed that this ending is theoretically drawn in the general case. (The rook can sacrifice itself for the bishop, after which KNN vs. K is drawn.)
Black is threatening checkmate in the above position: do whatever it takes to stop Black! But kindly do it in the right order.