One of my favorite security measures here at Perishable Press is the site’s virtual Blackhole trap for bad bots. The concept is simple: include a hidden link to a robots.txt-forbidden directory somewhere on your pages. Bots that ignore or disobey your robots rules will crawl the link and fall into the trap, which then performs a WHOIS Lookup and records the event in the blackhole data file. Once added to the blacklist data file, bad bots immediately are denied access to your site. I call it the “one-strike” rule: bots have one chance to follow the robots.txt protocol, check the site’s robots.txt file, and obey its directives.
Spritely is a simple plugin with only two key methods, sprite() and pan() both of which simply animate the background-image css property of an element. The difference between the two is that a 'sprite' image contains two or more 'frames' of animation, whereas a 'pan' image contains a continuous image which pans left or right and then repeats. Typically, in either case, you would use a png file (with or without transparency) for this. You might wish to use a transparent gif for Internet Explorer 6, though it probably won't look as good.