My wife and I each have a spending budget. Using Mint, anything we don't spend rolls over into the next month. My wife likes to spend hers every month on clothes, shoes, etc. I don't have much I want so just last week I was trying to figure where to invest my money. I thought about Loyal3 since it would be easy to send $50 or $100 a month to it and have it 100% invested. But I also wanted to try out Robinhood and invest in whatever stocks I felt like. But then I started thinking how I don't know anything about stock picking and how I'd prefer not to lose most of my money. I also wanted 100% of it invested and liquidity. So I ended up with Betterment. It's not "fun," but this way my spending money is fully invested and working for me until I find something big I want to spend it on. It also then allows me to make small deposits and I can buy/sell whenever I want without worrying about short term trading restrictions.
The rest of our money is invested in mutual funds, mostly index with the exception of Vanguard Wellesley and Wellington funds. Someday I'd like to invest in Lending Club again as it was fun with good returns while I tried it out for a couple of years.