Sure you can paste it, or you can look at the following which is the bare minimum that a block needs to function.
Remember that the .html part of a block doesn't require any code, so it can have anything you want in it.
Code:
<?php
function block_ads($params) {
if (!$params['template']) {
$params['template'] = 'block.ads.html';
}
$tpl = new Template;
$tpl->display("blocks/" . $params['template']);
}
?>
Remember to change function block_ads and 'block.ads.html' to correctly identify your block name.
As for the RSS you would need to code a new function in rss.php. I suppose it's not that hard to do as you could copy what is already there and modify it for your needs, but I haven't tried something like this before.