The issue here is that you have added all your banners, divided between clients and categories and you're looking for a solution which doesn't involve installing a 3rd party applicatoin.

 Unfortunately the Joomla banner module only supports alternating between banners of either the same client OR the same category.  The setting is in your Joomla > Module Manager > Banner... What I do is I don't select a client but instead just select a category.  Set it to only display 1 banner at a time.  

If you want other categories to display, consider setting categories as vertical, horizontal and square banners.  This means that you can have 3 modules each displaying banners from each category and position these as appropriate.

The Issue

Basically that you've installed JoomlaEZ's ReCaptcha Integrator plugin to protect your forms ("type two words" captcha) and then installed K2 Comments to use it's own ReCaptcha.  If you try adding a comment, you may get something like the following:

Fatal error:
Cannot redeclare_recaptcha_qsencode() (
     previously declared in /public_html/plugins/system/jezReCaptcha/recaptcha-php-1.10/recaptchalib.php:47
)
in /public_html/components/com_k2/lib/recaptchalib.php on line 67

I've managed to fix this in my site. Because you already force the recaptcha feature in your registration form and contact form (on this website I just went recaptcha-happy), then there are some settings you need to change in the plugin options:

• Inclusion Syntax = NO
• Auto-verify =YES

Update 16.NOV.2009

I don't see this supported anymore so I wouldn't recommend using the JezRecaptcha plugin.  In fact I'm not impressed with Recaptcha as it's sound alternative doesn't work and the text form is hackable.

I will be changing this over throughout the site... I may keep recaptcha for the comments feature on K2 articles but it should be considered low security.

You can probably find this information of the rocket theme forum but I thought I'd put how I resolved this here.

 The issue is basically that you want the background to stay in its position in the browser while the rest of the elements scroll about.

1.  Go to Extensions -> Template Manager> Edit the CSS for the template
2. You should be given an option of css files, select styles.css and click on the Edit button 
3. Look for these lines:

            body.bgstyle1 #main-background {background: url(../images/backgrounds/bgstyle1/bgimage.jpg) 50% 0 no-repeat;}
       

4. where 1 is the number of the style of the template I am setting the background for and I add the "fixed" attribute to this id.  This will yield the following:

   body.bgstyle1 #main-background {background: url(../images/backgrounds/bgstyle1/bgimage.jpg) 50% 0 no-repeat fixed;} 
       

5.  Click on the 'Save' button.
6. The theme is getting it from a generated php file.  Look in the CSS folder of the template.
7. You should find a PHP file in this folder with the body.bgstyle# line you need to change as in steps 3 and 4.

This issue happened with a friend who was trying to upload extensions.  You should find that the configuration file is unwriteable (and that you can't change it using the joomla interface).

In the end to resolve this, he had to do a fresh install and double-checked the server settings for a subdomain. 

Hide Menu Item from Registered and Special

Refer to this link if you want to clean out a front-end admin interface with your website's style.  The following is from http://forum.joomla.org/viewtopic.php?f=32&t=252258&start=0 at this date/time.

Can't simply hide an item but can hide a menu (of course the menu could have been created with just one item with no title and positioned at the bottom of another menu; this would look like it was all part of one menu).

toubkal wrote:
This cannot be done by joomla administration but can be done by template code, you can have a module position in the template that is set to only show when the visitor is not logged in e.g. Code:

<?php if ( !$my->id ) {?> 
     <div id="topmod"><?php mosLoadModules ( 'top', -2 ); ?> </div>
<?php } ?>

Joomla extension disable menu link for registered users but not for public 

More Information: not so great, lot of text: 
http://help.joomla.org/content/view/476/146/

This took me a while to do so I thought I'd document it for future reference.

The Issue

See the restore default setting link at the bottom of this page in the footer?  I wanted to put one of the styled buttons behind it but then found that there's a lot more to do than just that.

Instructions

1. Open the templates/rt_affinity_j15/index.php
2. Look at the last few lines with the original code (below)
3. For this website template: 
   1. I've added the module-dark classes.
   2. Specified float:none to get rid of float:left
   3. Specified width of readon-wrap1 to the width of the button
   4. Specified margin:0 auto to center readon-wrap1

Original Code:

<?php if ($show_defaultsettings == "true") : ?>
	<a href="#" id="clear-cookies"><?php echo JText::_('DEFAULT_SETTINGS'); ?></a>
<?php endif; ?>

New Code:

<?php if ($show_defaultsettings == "true") : ?>
	<div style="overflow: hidden;float:none">
		<div class="module-dark readon-wrap1" style="float:none;width:200px;margin:0 auto">
			<div class="module-dark readon1-l"></div>
			<a href="#" id="clear-cookies" class="module-dark readon-main" style="margin-top:0px"><span class="module-dark readon1-m"><span class="module-dark readon1-r"><?php echo JText::_('DEFAULT_SETTINGS'); ?></span></span></a>
		</div>
	</div>
	<div class="clr"></div>		
<?php endif; ?>

The Issue

Basically that after upgrading Joomla, my TinyMCE WYSIWYG (What-you-see-is-what-you-get) editor halved its number of buttons and I couldn't add code snippets... 

The Fix

Just installed JoomlaFCK WYSIWYG Editor, an editor I use with my day job's MediaWiki software and it's pretty amazing.  Incredibly cross-browser compatible with some MS Office 2007 styling and fortunately maintains it's previous button layout.  The features such as full-screen editing, emoticons, and pasting from MS Word documents make it the best in the market IMO.

Joomla FCK Editor

You can download it for free from http://www.joomlafckeditor.com/ but you will need to register on their site first.