Having stayed at the Cosmo during our recent trip to LV, my friends and I found ourselves highly confused by hordes of people carrying pizza boxes, yet no pizza place in sight. Since we were usually not looking for food, we never bothered to ask anybody about it. Second to last night in LV, a drunken roommate, and a pizza craving finally allowed us to discover the hidden tunnel that leads to this magical place.
In case you didn't know, it's on the third floor of the Cosmo between Blue Ribbon Sushi & Jaleo. Make sure you go with time, and patience, because the line is usually down the hall, literally!
Being a native NYer, the pizza was decent. Although it wasn't AMAZING like most places back in NY, it was definitely worth the wait after a full day & night of partying in Vegas. It was exactly what we needed before heading to the airport at 6am.
Try it, trust, you'll thank me later.