I adapted the blink and button sketches to get the RGB led to change with each button pressed.

gistfile1.txt

 
// set pin numbers:
const int buttonPin1 = 6;     // the number of the pushbutton pin
const int ledPin1 =  11;  
const int buttonPin2 = 3;     // the number of the pushbutton pin
const int ledPin2 =  12;      // the number of the LED pin
const int buttonPin3 = 2;     // the number of the pushbutton pin
const int ledPin3 =  13; 
const int buttonPin4 = 5;     // the number of the pushbutton pin
const int buttonPin5 = 7;     // the number of the pushbutton pin
     // the number of the pushbutton pin  
// variables will change:
int buttonState1 = 0;        
int buttonState2 = 0;  
int buttonState3 = 0;  
int buttonState4 = 0; 
int buttonState5 = 0; 
 
void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin1, OUTPUT);      
  pinMode(buttonPin1, INPUT); 
  pinMode(ledPin2, OUTPUT);      
  pinMode(buttonPin2, INPUT); 
  pinMode(ledPin3, OUTPUT);      
  pinMode(buttonPin3, INPUT); 
  pinMode(buttonPin4, INPUT); 
  pinMode(buttonPin5, INPUT); 
  
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }
  
}
 
void loop(){
  // read the state of the pushbutton value:
  buttonState1 = digitalRead(buttonPin1);
  buttonState2 = digitalRead(buttonPin2);
  buttonState3 = digitalRead(buttonPin3);
  buttonState4 = digitalRead(buttonPin4);
  buttonState5 = digitalRead(buttonPin5);
  // check if the pushbutton is pressed.
  // if it is, the buttonState is HIGH:
  if (buttonState1 == HIGH) {     
    // turn LED on:    
    digitalWrite(ledPin1, HIGH);  
    Serial.println("btn1");
    delay(1000);
  } 
  else {
    // turn LED off:
    digitalWrite(ledPin1, LOW); 
  }
  
  if (buttonState2 == HIGH) {     
    // turn LED on:    
    digitalWrite(ledPin2, HIGH);  
    Serial.println("btn2");
    delay(1000);
  } 
  else {
    // turn LED off:
    digitalWrite(ledPin2, LOW); 
  }
  if (buttonState3 == HIGH) {     
    // turn LED on:    
    digitalWrite(ledPin3, HIGH);  
    Serial.println("btn3");
    delay(1000);
  } 
  else {
    // turn LED off:
    digitalWrite(ledPin3, LOW); 
  }
  if (buttonState4 == HIGH) {     
    // turn LED on:    
    digitalWrite(ledPin1, HIGH); 
    digitalWrite(ledPin2, HIGH); 
    Serial.println("btn4");
    delay(1000);
  } 
  else {
    // turn LED off:
    digitalWrite(ledPin1, LOW); 
     digitalWrite(ledPin2, LOW);
  }
  if (buttonState5 == HIGH) {     
    // turn LED on:    
    digitalWrite(ledPin3, HIGH); 
    digitalWrite(ledPin2, HIGH); 
    digitalWrite(ledPin1, HIGH);
    Serial.println("btn5");
    delay(1000);
  } 
  else {
    // turn LED off:
    digitalWrite(ledPin3, LOW); 
     digitalWrite(ledPin2, LOW);
     digitalWrite(ledPin1, LOW);
  }
  
}