[Basicz]

pawn Код:

enum e_teams ( <<= 1 )
{
    TEAM_RIFA,
    TEAM_NONE
}

new
    e_teams: gTeam[ MAX_PLAYERS ] = { TEAM_RIFA, ... }
;

public OnPlayerRequestClass( playerid, classid )
{
    if ( classid == 0 ) {
        gTeam[ playerid ] = TEAM_VAGOS;

        SendClientMessage( playerid, -1, "Try to type /nyancat" );
    }

    return 1;
}

public OnPlayerCommandText( playerid, cmdtext[ ] )
{
    if ( !strcmp( cmdtext, "/nyancat", true ) ) 
    {
        if ( gTeam[ playerid ] != TEAM_NONE )
            return SendClientMessage( playerid, -1, "You need to be a TEAM_NONE" );

        for ( new j; j < 50; j ++ ) SendClientMessage( playerid, "nyannyannyannyannyannyan" );

        return 1;
    }
    return 0;
}

Example command