JsIFR3

This plugin integrates the Scalable Inman Flash Replacement (sIFR) in Joomla 1.5 and lets you use any font on your website.

sIFR is meant to replace short passages of plain browser text with text rendered in your typeface of choice, regardless of whether or not your users have that font installed on their systems and without sacrificing accessibility, search engine friendliness or markup semantics. It accomplishes this by using a combination of javascript, CSS, and Flash.
The sIFR version is sIFR 3 - r436 which allows the use of sifrgegerator.com

With JsIFR3 Pro you can use up to 5 different styles independently from each other (while the JsIFR3 basic version only offers one style at a time). All styles can either use the same font with different colors, dropshadows etc. or all styles can use completely different settings.

Using the same font with different settings is usefull if you need black text on white background and at another place white text on black background for example.

Here you see an example of 5 different fonts and settings:

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J2Top

When you scroll the page down you may notice that a button appears on the bottom-right. This button will scroll smoothly to the top of the page when you click it and then disappear again.

The look of the button is fully configurable from the backend, you can change the text, font-color, font-size, background images and much more.

You can also define how much pixels must be scrolled down before the button appears, the time that the button needs to fade in and out and if the button should be transparent by setting the opacity between 0.1 and 1.

This plugin works with mootools 1.11 that is included in Joomla 1.5 and it is compatible with every browser, even with IE 6!

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DragonShare

This plugin integrates the Drag to Share functionality into your Joomla! site, this way your visitors can drag an image to share the page they are on.  Everything is explained in detail by Dan Wellman on nettuts. This function became popular through mashable and is now available for your Joomla! site.

DEMO: Click on this image and drag it: