just make a random case
like :
[php]
switch(randomint(3))
case1;
{
setdvar("g_gametype", "war");
break;
}
case2;
{
setdvar("g_gametype", "sd");
break;
}
case3;
{
setdvar("g_gametype", "ffa");
break;
}
[/php]
PS: I don't know it works , didn't tested it!