Ok i know that hexbugs dont have anyway to put your own program and codes into them, but is it possoble to change the cpu on it so it is possible to put programs into it. I want this so i can practice doing coding without having to use my teams robot. This way i can easily make simple programs and load them onto the hexbug to see if im doing it right. If it is possible to switch out the cpu's or have any kind of inexpensive small robot it would be very helpful.
Thanks!

Not that I'm aware of. The Hexbug isn't something that we support, so I'm not sure what your options are.

Have you looked at Robot Virtual Worlds: http://www.robotc.net/download/rvw/ You can write ROBOTC programs and run them in a simulated environment, which I think would let you achieve your goal of practicing programming without taking your teams robot.

Yes I have thought about virtual worlds. The problem is that I can't figure out to get the program I wrote into the virtual worlds software. Is there a tutorial video that shows how?

We have a Virtual Worlds walkthrough on our wiki you may want to take a look at, it will get you started with setting up and running Robot Virtual Worlds: http://www.robotc.net/wiki/Virtual_Worlds

Ok so I did what the intructions said and it just let me use the preprogrammed robot. It wasn't even my code. How could I do example make my own sack attack robot then put it on a sack attack world?

Unfortunately Robot Virtual Worlds does not have the option to make your own robot and use it in an Virtual World; however, it is something the RVW team is currently working hard to develop and we hope to have it out at some point later this year. We will post information on our blog as soon as it become available (www.robotc.net/blog), so keep an eye out for updates!

In response to the question on the OP:
http://blog.makezine.com/2011/08/03/ski ... g-hacking/
It is possible to hack a hexbug. (I haven't done so, though.) The procedure used doesn't relate to ROBOTC, but it is kinda cool.