This was initially written with rubiX users in mind, but since it's a bit more general now I thought I'd post it here.
Watching the same transition animations over and over is boring. You can speed them up with Spare Parts or you can just shut them off entirely within settings. There is, though, a third road: change 'em.
These are videos of most of the transition animations packs (Drod's rubiX animations, Fab's animation mix, and Android Stock have no videos at present).
There are two preferred ways to use these animations:
1. Add Animations Using Metamorph: should work for most roms. Thanks Haxzamatic!
Transition Animation MetaMorph Files - http://bit.ly/gwEB5F
Note: there is no current MetaMorph file for either Android Stock or Fab's mix (see below).
2. Manually Add Animations: should work for most roms
This process will be helpful for those wanting to mix and match animations from the folders. In fact, why don't you create your own mix and post it here so everyone else can appreciate your awesomeness. I'll add new mixes below if they come in.
1. Simply get ahold of the anim folder with the animations you want to use and the framework-res.apk from the rom you're interested in modifying (/system/framework/framework-res.apk).
2. Open up the framework-res.apk in 7zip (right click on it, and select "open archive").
3. Drag the anim folder with the animations (which you can download below) into /res folder in your framework-res.apk. This will replace the files currently in /res/anim.
4. Exit out of 7zip.
5. You now need to push the modified framework-res.apk onto the phone. You can do this by placing the modified framework-res.apk in the root sdcard folder, and entering the following into terminal emulator on your phone or using ADB when the sdcard is mounted:
mount -o rw,remount -t ext3 /dev/block/mmcblk1p21 /system
cp /sdcard/framework-res.apk /system/framework
mount -o ro,remount -t ext3 /dev/block/mmcblk1p21 /system
If you're using terminal emulator, your phone will probably reboot before you finish re-mounting and/or typing reboot.
NOTE: This is taken almost wholesale from MagnusRagnarok (initial post) and ronhova (detailed instructions) on XDA; they deserve the credit. Link To Original Post.
Since this process modifies your rom's framework-res.apk, it obviously won't work with other roms. Translation: don't take the framework you've just modified and try to put it on other roms. IF YOU DO THIS, YOU WILL DIE.
Animation Files: for manual addition
Drop In (from Drod's rubiX focused series)
Fly In and Flip Mix (from Fab's Apex)