I have done something like this before for someone from UK and I think I can help u.
Hello, I worked with arduino and C/C++ style very often for the last 6 years and I can do what you want VERY EASILY (animate your leds randomly as you have described). It will take me just some hours to complete this. I'll just need some informations about your arduino card but It will be easy for you to give me that. Thanks!