Default Do it yourself spoken alerts.
This is quite a lot of fun...

Instead of having all those boring beeps and alerts what about getting your XDA to actually speak to you instead.

1. Goto the http://www.research.att.com/projects/tts/demo.html
2. Enter the text you want spoken (eg. 'You have a new SMS message.')
3. Select the voice you want used
4. Click 'Speak' to render the .WAV file
5. Rename & copy the .WAV file to your XDA
6. Through Settings - Personal - Sounds & Notifications select your new alert.

Easy and a load of fun.