Any time you're wearing cleated shoes, you need to bring an extra pair of footwear for backup. Those spikes may work well in the soccer field, the track or the golf course, but it's going to be disastrous (at the least, annoying) once you step off the playing field. The Cleatskins make those backup shoes optional.
Instead of changing shoes after a game, you simply slip these footwear accessories over your cleated soles. No more carrying backup shoes and no more long ritual of changing -- you can wear the Nike Dunk NG you used at the country club to get back home right after. When worn, it covers up all the spikes, allowing you to get off the field and stride off without potentially breaking them (so you don't have to buy new shoes every couple of months), apart from sparing your rugs, floors, and tiles from damage.
Cleatskins is made from Skintek rubber, a special compressed molded rubber formulation that dulls the impact of spikes on the inner side while providing adequate traction on the exterior. It's available in different variants for wearing on specific types of shoes, including ones for soccer shoes, baseball shoes, and more. Rubber, plastic, and metal spikes are all fair game, as well.
Since they're just slip ons designed to wear over your soles, they won't take up considerable space in your bag. In fact, you can probably roll these up and cram them into a side pouch. They come in different colors and designs, too, so you can pick ones that match whatever pair of kicks you're going to be wearing.
You can buy Cleatskins now, priced at $24.95 for adult sizes and $19.95 for the kids versions.