All eyes will be on Pro Tour Kaladesh this weekend, and with SCG Regionals also featuring Standard, that's the format du jour. That means that Modern is floating under the radar right now, and while the effects of a new set are always smaller on a larger format, they can still be quite significant.
The problem with Madcap Experiment is that you really want to limit the number of artifacts in your deck so you can reliably hit something sweet off of it, but the more you do so, the more you risk taking a whole boatload of damage, perhaps enough to lose the game on the spot. That's where Platinum Emperion comes into play.
Because Madcap Experiment's text instructs you to put the revealed artifact onto the battlefield and then take the damage, Platinum Emperion will be there to stop your life total from changing, effectively negating the downside of the card and giving you a four-mana Platinum Emperion.
There are plenty of decks in Modern where that by itself is a big game, especially Burn. But because it only takes up six slots in the deck, you get to surround it with all the great cheap spells that were the hallmark of U/R Twin for years. Vendilion Clique is there to clear the way. Mana Leak, Remand, Spell Snare, and the no doubt tilt-inducing Disrupting Shoal are there to protect your Platinum Emperion once it's on the battlefield.
I'd like to see a Dispel in the maindeck as well, given that Path to Exile has been on the rise recently in Modern, but just like Twin, the list is highly customizable based on your expected metagame and personal preferences.
Simian Spirit Guide is a cheeky addition to help power out your Platinum Emperion in matchups where it's a home run, as well as landing Blood Moon on turn 2, which can knock out even the most-prepared Modern decks if they aren't careful about fetching basics early.
My favorite part about the Madcap Experiment win condition is that it adds even more versatility to Snapcaster Mage. It makes you much more resilient to discard spells, forcing your opponents to play more aggressively than they otherwise might and be more vulnerable to your normal control game plan. And there's nothing more U/R in Modern than putting your opponent in the squeeze like that. Welcome to the family, Madcap Experiment.