Snippet to display the registrations custom questions within the thank you table - http://take.ms/bp7Ba

custom_function.php

<?php
//Do not include the opening PHP tag if you already have one.

function ee_display_questions_on_thank_you_table($registration) {

	if( count($registration->answers()) > 0 ) {
	?>
		<tr>
			<th width="50%">
				<?php _e("Questions",'event_espresso')?>
			</th>
			<th width="50%" class="jst-left">
				<?php _e("Answers",'event_espresso');?>
			</th>
		</tr>
	<?php
	    foreach ( $registration->answers() as $answer ) {
	        if ( $answer instanceof EE_Answer ) {
	            //d($answer->question());
	            echo '<tr>';
		            echo '<td width="50%">';
		            	if ($answer->question() instanceof EE_Question) {
		            		echo $answer->question()->display_text();
			            	echo '<br>';
		            	}
		            echo '</td>';
		            echo '<td width="50%" class="jst-left">';
			            $answer->e_value();
			            echo '<br>';
		            echo '</td>';
		        echo '</tr>';
	        }
	    }
	}
}
add_action( 'AHEE__thank_you_page_registration_details_template__after_registration_table_row', 'ee_display_questions_on_thank_you_table' );