A quartet of South Florida hotels are offering a unique group activity: pop-up mural painting. The 100-room Gates Hotel Key West, the 145-room 24 North Hotel Key West, the 339-room Newport Beachside Hotel & Resort and the 152-room National Hotel South Beach all work with Unconventional, an artists' collaborative that will help groups of up to 100 create a pop-up mural over the course of a few hours. Cost: Starts at $4,500 for customized artwork.