I bought into Litecoin at under $5 with some hobby money some months ago and it's hanging out at $30. I cashed out my original investment (leaving several times that in Litecoin, yay profit), bought ten Radeon cards and some cheap motherboards with the money, threw together some Debian USB sticks in an evening and am now mining on P2Pool for shits and giggles.
In a few weeks the equipment will have paid for itself, even accounting for the insane difficulty increases. Power is cheap here, so I will do pretty well for a while yet. Bonus: the rigs run hot so I'm basically making a little money heating my house.
You can laugh all you want. I'm having a blast, I've made a tidy profit, I have a bunch of new toys to play with, and if Litecoin ever does go ballistic like Bitcoin did I won't be left on the sidelines like you will. Don't really care about the likelihood of *coins taking over the world, or whatever - there is money to be made and I'm happy to make it.
It's a fun hobby. Honestly, it's play money to me and I've multiplied it several times. Not complaining. More fun than hitting the casino like some people I know, even if it's gambling all the same.