Once I downloaded a whole lot of robots from the MetaTrader codebase site and gave them each a quick back-test. Most of them bombed (but to be fair, I didn't adjust any settings, and barely read any available documentation that came with them).
This EA was inspired by one such robot found on that site, available here. They post their own back-test results, and they're impressive. I couldn't get it to work properly in my own back-test, but I had a quick look at the code and implemented by own version of it.
Quickly back-testing it (60 minute EURUSD, 1-1-2011 to 1-1-2012, stop-loss 30, trailing-stop 50) gave these results:
An impressive 89% return, but only a 43% win rate.
Sadly, AUDUSD and GBPUSD don't fare so well:
Additionally, this robot places an awful lot of trades, and from looking at the EURUSD equity curve, most of the profit comes from about 7 big jumps (possibly 7 big trades). Not a good sign.
Despite the impressive EURUSD results, this is a bad, bad robot.