What simple investment options are there beyond stocks, bonds, and CDs?

In summary, I’m looking for an easy, medium- to long-term investment other than stocks, bonds, and CDs. Details below.

We’re currently in a market situation where the major stock market indexes are within a few percent of their all-time highs despite terrible on-the-ground economic conditions. In my mind, this makes stocks a somewhat dubious investment, with potentially lots of bankruptcies forthcoming.

On the other hand, interest rates are at next-to-nothing. CDs are definitely not keeping up with inflation, and bonds…well, it seems like interest rates have nowhere to go but up (not in the immediate future, but eventually, driven by inflation if nothing else), which makes bonds a questionable investment at the moment as well.

Basically, I’m not sure what to invest in during a market like this. I’m looking for another class of investment beyond the three listed. A few notes, however:

1. I want "easy" investments, click-and-forget style. So even though buying and renting a house might make a lot of sense in a low interest rate environment, it’s more of a hassle than I want right now.
2. Gold is not an investment, it’s a bet on the future value of the dollar. Similarly with other individual currencies and commodities. (I don’t know enough about commodity funds to know whether they should be tarred with the same brush or not.) I’m looking to make an investment, not a bet. (Yes, I realize that every investment decision is essentially a bet against the future, but I want something that can grow value in its own right, not just relative to inflation.)
3. No short selling or similar market bets. Again, I’m looking for an investment, not a bet. I might think stocks are currently overvalued, but I don’t claim to know whether the correction is coming in one month or twelve, or if it will come sharply or as a slow stagnation relative to inflation.
4. The ideal investment(s) will perform at least moderately in a low interest rate, high stock price environment, as these conditions may well persist for some time.

Any ideas would be appreciated.