Invest some money in volatile stocks, that will keep you busy all day.
Fuck that. Knowing me I'd be on that shit 24/7, nails worn down to the knuckle and constant anxiety.
I'm addicted to amazon/ebay/buy.com because I'm selling a lot of shit on there. Around 1,000 items a month average. I'm always replying to stupid customer emails, checking and updating listings, payment transfers...etc.
I'm getting it down to a science to save time but I'm still on there way too much, just wasting time. I'd rather check out new interesting websites where I can learn shit about anything and everything to see what other interests I can pick up.