I don't do a lot of audio/video stuff with my system, but the other day I had the urge to see if there was some voice synthesis software available on Linux and it turned out that I already had it installed: it's called Festival.
If you're a Vonage user and you'd like to keep tabs on your bill as the month progresses, the script described here can help. The script uses curl to login to your Vonage account and download the web page with your current balance.