In answer to this: http://gamedev.stackexchange.com/questions/63411/getting-collision-detection-in-pygames

main.py

import pygame
import random
from pygame.locals import KEYDOWN, K_LEFT, K_RIGHT, K_UP, K_DOWN, QUIT

# init pygame, with white background 500x500 pixels in size
pygame.init()
screen = pygame.display.set_mode((500, 500))
background = pygame.Surface((500, 500))
background.fill((255, 255, 255))

# init a sprite
player = pygame.sprite.Sprite()
# set its size to 40x40, position to 0, 0
player.rect = pygame.Rect(0, 0, 40, 40)

# image is 40x40 grey block
player.image = pygame.Surface((40, 40))
player.image.fill((60, 60, 60))

# init a sprite
block = pygame.sprite.Sprite()
# set its size to 20x20, position to 300, 300
block.rect = pygame.Rect(300, 300, 20, 20)

# image is 20x20 green block
block.image = pygame.Surface((20, 20))
block.image.fill((60, 200, 60))

def handle_input():

    for event in pygame.event.get():

        if event.type == QUIT:
            return False

        # if user presses a key
        if event.type == KEYDOWN:
            # arrow keys move the player
            if event.key == K_LEFT:
                player.sprite.rect.x -= 40
            elif event.key == K_UP:
                player.sprite.rect.y -= 40
            elif event.key == K_RIGHT:
                player.sprite.rect.x += 40
            elif event.key == K_DOWN:
                player.sprite.rect.y += 40

        # collide_rect checks collision between two sprites
        if pygame.sprite.collide_rect(player, block):
            # move block to a new position
            block.rect.x = random.randint(20, 480)
            block.rect.y = random.randint(20, 480)
            print "You ate a block!"


def draw():
    screen.blit(background, (0, 0))
    screen.blit(player.image, player.rect.topleft)
    screen.blit(block.image, block.rect.topleft)
    pygame.display.update()

while True:
    if handle_input() is False:
        break
    draw()