Scatter brownie cubes in the bottom of a wide, shallow bowl. Slice bananas in half lengthwise, and place them on top of the brownies, fanning outward in a circle. Top the bananas with scoops of ice cream. Drizzle the ice cream with fudge, caramel, and/or strawberry sauces. Garnish with cookies, whipped cream, sprinkles, cherries, or anything else you can dream up! The ice cream will start to melt fairly quickly, so pass out the spoons and dig in!
If you have the freezer room, I recommend pre-scooping the ice cream. Because the ice cream will start to melt as soon as it is scooped, and you'll buy yourself a few extra minutes of perfect banana split appreciation if you use frozen scoops of ice cream. Line a baking sheet or two with waxed paper, and soften the ice cream at room temperature for 5-10 minutes. Scoop the ice cream onto the sheets and return to the freezer until you're ready to assemble. Once it's go time, plop the pre-scooped ice cream on top of the bananas, finish assembling, and admire your handiwork before diving in!