I'm the author of Event Organiser plug-in, and some users have noticed a conflict between it and the Easing Slider plugin.
The source of this conflict is that the Easing Slider plug-in, de-registers the jQuery version (jQuery 1.7.1 in WP3.3) that comes with WordPress and registers version 1.4.2. This causes the 'full calendar' shortcode to not render events, (I believe what ajax returns was changed in jQuery 1.5).
Is this plug-in able to operate with (preferably) jQuery 1.7.1 or at least jQuery 1.5?
Another solution, which would ensure greater compatability with other plugins is to register jQuery 1.4.2 as 'jquery1.4.2' rather than over-riding 'jquery'. This would also involve putting it in a no-conflict wrapper: see this post. (In practise this maybe more tricky to do in WordPress, I shall contact wp_hackers). Potentially this would allow both jQuery versions to be used and prevent conflict with other plugins.