front-page.php

<?php

/**
* Custom front page template
*/

remove_action( 'genesis_loop', 'genesis_do_loop' );

add_action( 'genesis_loop', 'genesis_sample_do_loop' );

function genesis_sample_do_loop(){
	genesis_grid_loop( array( 
		'features' => 2,
		'feature_image_size' => 'featured-image',
		'feature_image_class' => 'alignleft post-image',
		'feature_content_limit' => 200,
		'grid_image_size' => 'grid-thumbnail',
		'grid_image_class' => 'aligncenter post-image',
		'grid_content_limit' => 200,
		'more' => __('(More information...)', 'genesis-sample')		
	) );
}

functions.php

<?php
// Add grid image sizes
add_image_size( 'grid-thumbnail', 200, 100, TRUE );

style.css

/* # Grid Loop
---------------------------------------------------------------------------------------------------- */

.genesis-grid{
	padding: 20px;
	margin: 0 0 20px;
	width: 48%;
}

.genesis-grid-even{
	float: right;
}

.genesis-grid-odd{
	clear: both;
	float: left;
}