Josh sent the following about RNVS:
This one can’t keep going up forever! What are your thoughts on shorting it? The stochastic indicator looks like a prime candidate for a short – I’ve been watching it since the 93% move on 5/4/05.
Ah, the lure of the counter-trend trade. I’ve certainly been there and done that before. Actually some of my biggest trades have come from shorting moon-shot stocks but man, if you don’t time them right they can be deadly. I don’t try them very often for that reason. I certainly agree that RNVS, or any stock, can’t go up (at this rate) forever but that doesn’t necessarily mean that it will drop much either. If you want to try shorting these type of movers I think you should wait until it starts going down (maybe breaks a short-term moving average) and/or wait for a bearish candlestick pattern to be confirmed.
On a related note, I traded RNVS a couple of times last week. It’s been printing some beautiful ‘dummy‘ spots on which to get long. Too bad I didn’t just buy it and hang on to it — I’d be up about 30% from my first purchase which was just over $13. Instead I walked away with lunch money. 
Here’s an intraday chart showing the action over the last 5 sessions (30-minute candles):
