Outline:

(really good game) everyone stands in a circle. Splat master goes in the middle.  The splat master ‘splats’ someone in the circle by pointing their open hand (no gun motion :P) and shouting splat.  That person ducks to avoid the splat and the two people on either side have to try and splat each other. The fastest splatter wins (as decided by the splat master); the slower must sit down for the rest of the game.  If the first person doesn’t duck intimae, then they have to sit down for the rest of the game.  When only two people are left it is a splat-off.  They stand back to back in the centre of the circle.  The splat master picks a splatword, such as ‘spiderpig’, the splatmaster then calls out lots of words, the two finalists take a step further apart with each word, until the splat word is said, when they have to turn and be the fastest splatter.