One day a year, you have to deal with frosting. This is that day.
Though frosting itself doesn't take too much effort to clean up (we're hoping it's concentrated in little party plates you can dump in the garbage), because most frostings are butter-based, they'll leave behind an oily residue that will obstinately cling to clothing and home textiles. As with all stains, get anything that's been spotted with frosting into the washing machine as soon as possible, and make sure you've scraped off all the excess frosting, or you'll have a thin film of congealed butter on the entire load of clothing. Also, run the load on the hottest setting -- water by itself won't do much to combat a butter stain, but hot water can quickly melt out the oil and send it down the drain.