need help with ifelse statements

hey all.. i’m trying to write a simple little ifelse statement to filter out a couple categories … but i keep getting an error, and i’m not sure what’s wrong with what i have.. do you see anything jumping out at you ? all these endifs and endwhiles are confusing me

<?php if (have_posts()) : ?><?php while (have_posts()) : the_post(); { ?>
<?php if ( in_category('10') ) { ?>
// ignore category 10 and do nothing and move on
<?php } ?>
<?php elseif ( in_category('3') ) { ?>
// ignore category 3 and do nothing and move on
<?php } ?>
<?php else { ?>
&raquo; <a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title(); ?>"><?php the_title(); ?></a><br />
<?php } ?>
<?php endif; ?>
<?php } ?>
<?php endwhile; endif; ?>


any help would be greatly appreciated!