Yeah a friend of mine found one a while back which used java to mine on your machine (cpu only) - the key difference is you had to allow it to mine to take any effect

http://www.bitcoinplus.com/generate

The case with the ESEA the users had already allowed their program to access their computer so there was little anyone could do about it, it's just lucky it was found so quickly, it's quite undetectable especially if you're already playing games you might not notice that your cpu/gpu usage has gone way above what is needed