A fun one that I've spent way too much time playing with recently is called Shake Them All! by Yougli. It was released over a year ago but was just updated earlier this month, so it's still being supported.
It started out as a simple live wallpaper that used a "realistic physics engine" and the phone's sensors to make Android mascots move around on the screen. Today there are tons of user-made mascot skins (like the Michelangelo Teenage Mutant Ninja Turtle one shown at right) available through a built-in skin manager, options to use a color or an image as the background, the ability to change the mascot size and number of mascots on the screen, and settings to allow the items to react to gravity, acceleration, touch, light, and sound!
The quality of the graphics depends on their size, though I haven't been able to find any size that smooths out the lines completely. They look more jagged in the screenshots because they're always moving, but even in person, the rough edges are noticeable and the items always look a little pixelated.
The level of customization outweighs the imperfect graphics to me, as the seemingly endless combinations of skin choice, size, number, background color/image, and sensor sensitivity make it really enjoyable.
Enabling all the sensors will have a more dramatic impact on battery life than just using the bare minimum (gravity only), so you'll need to decide which is more important to you when you use this live wallpaper: watching mascots react to just about anything or making sure you don't miss an important call because you were tilting and rocking your EVO in every direction possible.
The physics don't seem to be quite as refined as they are in, say, the Liquid Physics live wallpaper, but it's fun to be able to tap one of characters and watch it jump up or tumble across the screen (set "reaction to touch" to 100% for best results), especially because the arms and legs swing around.
Some skins seem to affect general performance more than others, and I noticed that after changing skins a few times, subsequent changes wouldn't "stick" until I went back to the settings and re-applied the wallpaper. I also experienced one force close when browsing the skin manager, which is actually still a bit rudimentary. It would be nice if the Shake Them All! website, which is where you go to upload your own skins, offered some sort of "send to phone" feature or if there was a way to search for specific skins on the phone. Skins you select and use are downloaded to your SD card, but I don't see an option to access them from within the wallpaper's settings; a library or "My Skins" option in the settings would be nice to see in a future update.
Even so, Shake Them All! is a fun, addictive, and time-wasting live wallpaper to check out your EVO.