I’m looking to make a countdown video that features 3d rendered numbers, but I can’t find anyway to animate changes to text. I know I could just do it the hard way and create all the numbers and just hide/unhide them as needed, but that would take a very long time that I’d like to avoid. If anyone knows a technique to pull this off, it would massively helpful.
http://www.geoffmartin.co.uk/blog/2-blog/4-countdown-timer-using-blender-3d
Maybe maybe this is something you search for…if you have another solution I wood like to hear it as well.
Martijn.
You´ll have to write a python script to do that changing the content of the text object.
I needed the same for a video lately but I am no python coder, so I just gave the job to our Adobe AE wizard and got a video back with the animated text a minute later and used it as animated texture 
you could do it by setting layer keyframes and switching objects, but it’s a pain to do in 2.5, so i would reccomend using 2.49