Airsoft is a sport that uses fake guns to battle. Plastic balls, called BBs are shot out of the guns. For safety, players wear protective goggles and masks. There are many kinds of airsoft guns. There are ones powered by springs, electric motors and compressed gasses. Almost all are modeled after real guns.
Games can range from 20 minute deathmatch style games to full on military themed exercises lasting for 24,36 or 48 hours. The goal of airsoft is to play at combat realistically but without serious injury. Players can get hit, but usually only get bruises or small cuts.
Laws about airsoft are different in each country. Some airsoft guns look like real guns. Some can even fire automatically. In some countries, there are strict laws about airsoft, and others have completely outlawed it.