I remember one called Reshack or something thats safe, but id look up what it does etc and be sure you know what your doing first. My college (uk college) wouldnt let us use firefox so i come up with the genious idea of having one called internet explorer..therefore they couldnt block it
If your planning on running this at a workplace, im pretty sure A: the firewall may be a problem, B: theres alot of ways you'd probs get caught sooner or later, playing games C: You are getting paid to work, work
This is combined with the memory stick idea too, I am not responsible for any problems that are caused either should there be any. Just to let you know, if your planning on running multiple copies of guild wars or soemtihng, theres many simpler ideas and legal programs that you can use.