I used to play penny stocks for fun and it was a blast to be doing $3000 trades and be responsible for 30% of the volume for the day. You can learn a lot about how markets work if you adopt a penny stock, particularly the kind that trades in a wide range where you can buy in at 0.03 and figure "I'll sell when it hits 0.12" and sooner or later it does... then falls back down to 0.02.
You can "trade the news" with penny stocks (this is basically just buying when people first start talking about it then selling when more people are talking about it), but like you say, the liquidity is soooooo low that you have to be really careful if you plan to sell more than a few hundred dollars.
Generally, you're going to lose money - so don't do it.
This is interesting to me. I never had any enjoyment from traditional gambling when I dabbled in it. But I like the idea of being an expert on a little-known company and experiencng the response of my actions. Of course, it would be "for entertainment purposes only."
I was never interested in market timing, though.